Development Of Cellular Immunity Research Articles

Effect of Porcine Colostral Exosomes on T Cells in the Peripheral Blood of Suckling Piglets.

Simple SummaryExosomes in porcine colostrum have gained attention as the possible key compounds involved in the growth and/or development of suckling piglets. In this study, peripheral blood mononuclear cells (PBMCs) from suckling piglets were cultured with or without milk-derived exosomes (control) in vitro. Porcine colostral exosomes increased the proportion of cytotoxic T (Tc) cells, while this phenomenon was not observed in PBMC whose endocytosis was inhibited. Moreover, exosome-treated PBMCs had a higher cytokine IL-2 concentration in the culture supernatant than the control. The present study demonstrated that porcine colostral exosomes could increase the Tc cell proportion in the peripheral blood of a suckling piglet, with the underlying mechanism believed to be the stimulation of IL-2 production in PBMCs via endocytosis.Growing evidence indicates that porcine colostral exosomes may contribute to the healthy development of piglets. Here, we evaluated in vitro the effect of porcine milk-derived exosomes, in particular colostral exosomes, on T cells in the peripheral blood of suckling piglets. A total of seven sows and thirteen suckling piglets were used. Peripheral blood mononuclear cells (PBMCs) from suckling piglets were cultured with or without milk-derived exosomes (control). Using flow cytometry, the proportion of each T cell subset in cultured PBMCs was analyzed three days post-incubation. PBMCs cultured with porcine colostral exosomes had a higher proportion of CD3+CD4−CD8+ T cells (cytotoxic T cells; Tc) than the control. However, exosomes induced no increase in the Tc cell population in PBMC whose endocytosis was inhibited. We further measured the concentrations of cytokines in the culture supernatant. Exosome-treated PBMCs had a higher cytokine IL-2 concentration than the control. The present study demonstrated that porcine colostral exosomes could increase the Tc cell proportion in the peripheral blood of suckling piglets, with the underlying mechanism believed to be the stimulation of IL-2 production in PBMCs via endocytosis. Moreover, our results suggested that porcine colostral exosomes were involved in the development of cellular immunity in suckling piglets.

T Cell Repertoire During Ontogeny and Characteristics in Inflammatory Disorders in Adults and Childhood.

Since the first day of life, a newborn has to deal with various pathogens from the environment. While passive immune protection is provided by diaplacental maternal antibodies, the development of cellular immunity is ongoing. A mature immune system should be able not only to defend against pathogens, but should also be able to differentiate between self- and non-self-antigens. Dysregulation in the development of cellular immunity can lead to severe disorders like immunodeficiency, autoimmunity and chronic inflammation. In this review, we explain the role of T cell immunity in antigen detection and summarize the characteristics of a mature TCR repertoire as well as the current state of knowledge about the development of the TCR repertoire in ontogenesis. In addition, methods of assessments are outlined, with a focus on the advantages and disadvantages of advanced methods such as next generation sequencing. Subsequently, we provide an overview of various disorders occuring in early childhood like immunodeficiencies, autoimmunity, allergic diseases and chronic infections and outline known changes in the TCR repertoire. Finally, we summarize the latest findings and discuss current research gaps as well as potential future developments.

Immunobiological status of the body of cows during mastitis

The work reveals the immunobiological aspects of lactation of cows and changes in immunobiological reactivity in the development of mastitis.The authors present modern scientific data on the local immune protection of the mammary gland of cows. Main stages of ontogenetic development of cellular immunity of the mammary gland of cows were traced during clinical and experimental studies. The number of somatic cells in the secret of the mammary gland of the primates was dependent on the period of the functioning of the mammary gland. In the cytology of colostrum mostly (56.00 ± 1.90%) neutrophil granulocytes were predominant, in the middle period of lactation (3–5th month) the proportion of epithelial cells increased (from 29.51 ± 2.17 to 49.59 ± 1.94%), during the launch period, the population of polymorphonuclear neutrophil granulocytes was changing as well, which virtually recovered to the original level and increased during the dry period. However, at the end of lactation, during the onset and dry, with the development of involutionary processes in the mammary gland, a sharp decrease in cytochemical reactivity of intracellular lysozyme of phagocytic cells was observed. To conduct clinical and experimental studies, three groups of animals were formed. As a result, it was found out that subclinical mastitis of cows is accompanied by a change in the immunobiological reactivity. Purulent-catarrhal mastitis in cows was manifested by significant changes in the parameters of nonspecific immunological reactivity. In the peripheral blood of cows with subclinical mastitis, the number of reactive microphages increased sharply (P < 0.001). In parallel with this, the number of activated phagocytes with myeloperoxidase granules also increased in the peripheral blood (P < 0.01). Activation of intra-leukocyte lysozyme phagocytic cells was less intensive. Subclinical udder pathology was accompanied by an increase in the number of degranulated cells (P < 0.001), which is one of the specific properties of cytomorphological changes in programmed death (apoptosis). Subclinical inflammation of the mammary glands mastitis of cows was accompanied by a certain decrease in the number of T-lymphocytes (P < 0.001). Clinical and experimental studies have shown that subclinical and purulent-catarrhal mastitis of cows undergo significant changes in systemic immunity. In the pathophysiological model of subclinical and purulent-catarrhal mastitis, the functional state of the T-link of specific immunity was disturbed, the bactericidal activity of blood serum and phagocytosis were suppressed, which occurred against the background of changes in the cytochemical reactivity of phagocytic cells circulating immune complexes and molecules with an average molecular weigh.

Chemoprophylaxis of leprosy with rifampicin in contacts of multibacillary patients: study protocol for a randomized controlled trial

BackgroundThe annual new-case detection rate for leprosy, while generally stable over the last decade, shows that transmission rates have remained stagnant despite the successful worldwide administration of multidrug therapy since the 1980s. As such, novel control strategies are urgently needed. Focusing on managing leprosy patient contacts, the most susceptible to contracting the disease, has been seen as a potential strategy in limiting the spread of leprosy as shown by a number of recent epidemiological studies. Immunoprophylaxis with Bacillus Calmette-Guérin (BCG) has been seen as an effective preventive measure due to its ability to stimulate the development of cellular immunity which is essential in controlling the disease, especially in its multibacillary (MB) forms. The association of immunoprophylaxis with chemoprophylaxis in a single dose of rifampicin has been shown to be a promising preventive strategy, although a variety of studies have found instances of early case detection just a few months after BCG vaccination.Methods/designThe present study is a phase IV chemoprophylactic clinical trial consisting of administration of a single dose of rifampicin in MB leprosy patient contacts under care at the Souza Araújo Outpatient Clinic/FIOCRUZ as part of a randomized (2:1), double-blind, placebo-controlled study. It is comprised of two groups: 1) rifampicin + BCG; and 2) placebo + BCG.DiscussionThe aim is to evaluate whether the use of chemoprophylaxis with a single dose of rifampicin in MB leprosy patient contacts prior to the BCG vaccine would be able to prevent the onset of leprosy in those cases that may occur just a few months after vaccination. Contact subclinical infections (polymerase chain reaction) and the immunological parameters (anti-PGL-1, anti-LID-1, and IFN-γ) will be evaluated and the results will be compared after 12 months of follow-up.Trial registrationThe Brazilian Registry of Clinical Trials (ReBEC), RBR-69QK5P. Retrospectively registered on 1 June 2017.

Онтогенетичні особливості формування локального імунного захисту молочної залози корів (огляд літератури та оригінальні дослідження)

The authors present modern scientific data on the local immune protection of the mammary gland of cows. Main stages of ontogenetic development of cellular immunity of the mammary gland of cows were traced during clinical and experimental studies. The number of somatic cells in the secret of the mammary gland of the primates was dependent on the period of the functioning of the mammary gland. In the cytology of colostrum mostly (56.00 ± 1.90%) neutrophil granulocytes were predominant, in the middle period of lactation (3–5th month) the proportion of epithelial cells increased (from 29.51 ± 2.17 to 49.59 ± 1.94%), during the launch period, the population of polymorphonuclear neutrophil granulocytes was changing as well, which virtually recovered to the original level and increased during the dry period. The cytochemical reactivity of intracellular lysozyme of phagocytic cells in the secretion of the breast of the primates was from the beginning of lactogenesis and in the middle period of lactation (3-5th month) almost constant. However, at the end of lactation, during the onset and dry, with the development of involutionary processes in the mammary gland, a sharp decrease in cytochemical reactivity of intracellular lysozyme of phagocytic cells was observed. A similar trend was observed in the phagosomal activity of lysosomal cationic proteins. The greatest reactivity of phagocytes was shown in the beginning of lactogenesis in reaction to lysosomal cationic proteins, which acquired its maximum manifestation in the middle period of lactation and gradually decreased at the end of the lactation period. In the period of launch and dry in the secretion of pricking cessation, there was a cytochemical activation of oxigen-dependent factors of protection of phagocytic cells. Consequently, the formation of cellular immune defense takes place in the process of ontogenetic development of the mammary gland of cows. In the firstborn, simultaneously with the formation of secretory function of the mammary gland, there is a gradual formation of natural factors protecting the body. Oxygen-independent and Oxygen-dependent factors of phagocytic protection of the breast of the firstborn are not sufficiently formed, their activation is started from the colostrum period and undergoes a physiological fluctuation throughout the lactation period.

Serum levels of interleukin-12 in various clinical states with hepatitis B virus infection

Hepatitis B virus (HBV) infection involves various clinical states. Interleukin-12 (IL-12) has been identified as a crucial cytokine in the development of cellular immunity. But the association between HBV infection clinical states and cellular immunity response remains unclear. The aim was to explore the association by investigating serum levels of IL-12. Observed in acute hepatitis B, the highest serum levels of IL-12 was accompanied by HBeAg seroconversion. Serum levels of IL-12 was associated with alanine transaminase (ALT) levels and significant more in chronic hepatitis B patients with ALT over five times upper limit of normal and a minority of immune-tolerance patients than controls. Serum levels of IL-12 may be an available marker to evaluate cellular immunity for HBV infection. Elevation in IL-12 levels may be a factor to promote HBeAg seroconversion and an opportunity to be given antivirus treatment for immune-tolerance carriers.

Immune Modulation through 4-1BB Enhances SIV Vaccine Protection in Non-Human Primates against SIVmac251 Challenge

Costimulatory molecules play a central role in the development of cellular immunity. Understanding how costimulatory pathways can be directed to positively influence the immune response may be critical for the generation of an effective HIV vaccine. Here, we evaluated the ability of intravenous administration of a blocking monoclonal antibody (mAb) directed against the negative costimulatory molecule CTLA-4, and an agonist mAb directed against the positive costimulatory molecule 4-1BB, either alone or in combination, to augment intramuscular SIV DNA immunizations. We then tested the ability these of these responses to impact a high-dose SIVmac251 challenge. Following immunization, the groups infused with the anti-4-1BB mAb exhibited enhanced IFN-γ responses compared to the DNA vaccine only group. Interestingly, although CTLA-4 blockade alone did not enhance IFN-γ responses it did increase the proliferative capacity of the CD4+ and CD8+ T cells. The combination of both mAbs enhanced the magnitude of the polyfunctional CD8+ T cell response. Following challenge, the group that received both mAbs exhibited a significant, ∼2.0 log, decrease in plasma viral load compared to the naïve group the included complete suppression of viral load in some animals. Furthermore, the use of the CTLA-4 blocking antibody resulted in significantly higher viral loads during chronic infection compared to animals that received the 4-1BB mAb, likely due to the higher CD4+ T cell proliferative responses which were driven by this adjuvant following immunization. These novel studies show that these adjuvants induce differential modulation of immune responses, which have dramatically different consequences for control of SIV replication, suggesting important implications for HIV vaccine development.

P19-49. Modulation of vaccine induced responses through CTLA-4 and 41BB enhances protection in macaques following SIVmac251 challenge

Background Co-stimulatory molecules play a critical role in the development of cellular immunity. Understanding how costimulatory pathways interact and influence the immune response is critical for the generation of an effective HIV vaccine. We evaluated the ability of intravenous administration of blocking monoclonal antibodies (mAb) directed against the negative co-stimulatory molecule, CTLA-4, and an agonist mAb directed against the positive co-stimulatory molecule, 41BB, to augment intramuscular SIV DNA immunizations. We then tested the ability of these responses to impact a SIVmac251 challenge.

Sand Fly Salivary Proteins Induce Strong Cellular Immunity in a Natural Reservoir of Visceral Leishmaniasis with Adverse Consequences for Leishmania

Immunity to a sand fly salivary protein protects against visceral leishmaniasis (VL) in hamsters. This protection was associated with the development of cellular immunity in the form of a delayed-type hypersensitivity response and the presence of IFN-γ at the site of sand fly bites. To date, there are no data available regarding the cellular immune response to sand fly saliva in dogs, the main reservoirs of VL in Latin America, and its role in protection from this fatal disease. Two of 35 salivary proteins from the vector sand fly Lutzomyia longipalpis, identified using a novel approach termed reverse antigen screening, elicited strong cellular immunity in dogs. Immunization with either molecule induced high IgG2 antibody levels and significant IFN-γ production following in vitro stimulation of PBMC with salivary gland homogenate (SGH). Upon challenge with uninfected or infected flies, immunized dogs developed a cellular response at the bite site characterized by lymphocytic infiltration and IFN-γ and IL-12 expression. Additionally, SGH-stimulated lymphocytes from immunized dogs efficiently killed Leishmania infantum chagasi within autologous macrophages. Certain sand fly salivary proteins are potent immunogens obligatorily co-deposited with Leishmania parasites during transmission. Their inclusion in an anti-Leishmania vaccine would exploit anti-saliva immunity following an infective sand fly bite and set the stage for a protective anti-Leishmania immune response.

HIV-1 Nef Inhibits Lipopolysaccharide-induced IL-12p40 Expression by Inhibiting JNK-activated NFκB in Human Monocytic Cells

Impaired cellular immunity caused by decreased production of Th1-type cytokines, including interleukin-12 (IL-12) is a major feature of HIV-1-associated immunodeficiency and acquired immunodeficiency syndrome. IL-12p40, an inducible subunit shared between IL-12 and IL-23, plays a critical role in the development of cellular immunity, and its production is significantly decreased during HIV infection. The mechanism by which HIV induces loss of IL-12p40 production remains poorly understood. We have previously shown that lipopolysaccharide (LPS)-induced IL-12p40 production in monocytic cells is regulated by NFkappaB and AP-1 transcription factors through the activation of two distinct upstream signaling pathways, namely the c-Jun-N-terminal kinase (JNK) and the calmodulin-dependent protein kinase-II-activated pathways. Herein, we show that intracellular nef expressed through transduction of primary monocytes and promonocytic THP-1 cells with retroviral-mediated nef gene inhibited LPS-induced IL-12p40 transcription by inhibiting the JNK mitogen-activated protein kinases without affecting the calmodulin-dependent protein kinase-II-activated pathway. In addition, nef inhibited JNK-activated NFkappaB without affecting the AP-1 activity. Overall, our results suggest for the first time that intracellular nef inhibited LPS-activated JNK, which may cause inhibition of IL-12p40 expression in human monocytic cells by selectively inhibiting NFkappaB activity.

New approach to study of T cellular immunity development: Parallel investigation of lymphoid organ formation and changes in immune proteasome amount in rat early ontogenesis

The expression pattern and distribution of proteasome immune subunits LMP7 and LMP2 in the developing rat spleen and liver as well as the periarterial lymphoid sheath formation were investigated. LMP7 and LMP2 were detected by immunoblotting in the spleen on the 21st embryonic day and during the first postnatal days in equal amounts. Their levels increased by the 8th and 18th postnatal days. Double immunofluorescent labeling the spleen cells revealed LMP7 and LMP2 in T and B lymphocytes localized in the red pulp in embryogenesis. Few T lymphocytes were discovered in periarterial zones on the 8th postnatal day. T lymphocytes filled these zones and formed lymphoid sheaths by the 18–19th day. In the liver, LMP7 and LMP2 were revealed by the 17–19th postnatal day. Immunofluorescent analysis showed their presence in hepatocytes at this period. The data suggest that T cell-mediated immune response in relation to hepatocytes is possible beginning from 18th to 19th postnatal day.

Prenatally Diagnosable Differences in the Cellular Immunity of Fetuses with Down’s and Edwards’ Syndrome

Introduction: Lymphocyte subpopulations are identified by the uniform CD classification (Cluster of Differentiation) and can be accurately differentiated with monoclonal antibodies using the method of flow cytometry. With the aid of cordocentesis it is possible to perform studies on the status and development of cellular immunity as early as in the second trimester of pregnancy. Objective: To compare lymphocyte subpopulations present in fetuses with chromosomal abnormalities (Down’s syndrome (DS), Edwards’ syndrome (ES)) and fetuses with normal karyotype. Study Design: Prospective observational study. Methods: We examined a total of 61 pregnant women with an average age of 31.5 years (20– 46 years). Results: In fetuses with DS we found a significant decrease in B lymphocytes (CD19),a decrease in the subpopulations of multi-reactive B-cells (CD5+CD19+, B-CLL),and a decrease in the index of CD4/CD8 and class II HLA-DR. In contrast, the representation of NK cells expressing /CD3-CD (16 + 56)+/ was greatly increased. In ES we found a decrease in T lymphocytes (CD3), a decrease in T-helper lymphocytes (monocytes CD4), a decreased index of CD4/CD8 and a greater representation of NK cells /CD3-CD (16 + 56)+/. Conclusion: We determined the normal values of lymphocyte subpopulations in physiological fetuses. We demonstrated that the immunological defect of the affected fetuses is already present antenatally, and can be reliably diagnosed in the second trimester of pregnancy.

Vaccination with cell immunoglobulin mucin-1 antibodies and inactivated influenza enhances vaccine-specific lymphocyte proliferation, interferon-γ production and cross-strain reactivity

SummaryInfluenza virus causes a contagious and potentially serious infection of the upper respiratory tract. While neutralizing antibodies are protective against infection, the problem of antigenic drift remains, requiring the constant monitoring and development of new vaccines. The magnitude of this situation is underscored by the emergence of new potentially human pathogenic influenza strains, avian H5N1 being the most recent example. We present evidence that antibodies against T cell immunoglobulin mucin-1 (TIM-1), a recently identified immunomodulatory molecule, stimulate cellular immunity against influenza viruses and cross-strain immune reactivity. To determine potential immunostimulatory properties of anti-TIM-1, mice were vaccinated with inactivated influenza virus in the presence or absence of TIM-1-specific monoclonal antibodies. Development of cellular immunity against both the influenza strain used for immunization and serotypically distinct virus strains was monitored 3 weeks after vaccination by determining antigen-specific lymphocyte proliferation and cytokine production. Results show that TIM-1 antibodies enhance antigen-specific cellular proliferation (P < 0·05) and interferon (IFN)-γ production (P < 0·01). Using blocking anti-CD4 and CD8 antibodies, it was observed that antigen-specific cellular proliferation is CD4-dependent and that the majority of proliferating cells are CD4+. Finally, vaccination with inactivated influenza virus with TIM-1 antibody results in the significant (P < 0·001) induction of proliferation and IFN-γ production upon stimulation with one of three serologically distinct strains. TIM-1 antibodies demonstrate an adjuvant effect promoting antigen-specific cellular proliferation and IFN-γ production, which are important for the promotion of cell-mediated immunity. These results are the first to suggest that TIM-1 antibody may serve as a potent adjuvant in the development of new influenza virus vaccines.

Gene therapy of a rat follicular thyroid carcinoma model with adenoviral vectors transducing murine interleukin-12.

Interleukin-12 (IL12) is a heterodimeric cytokine that plays an important role in the development of cellular immunity. We previously reported the antitumor activity of mouse IL12 (mIL12) transduced by adenovirus in a medullary thyroid carcinoma model. In this study, a rat thyroid follicular cancer cell line (RTC-R2) was employed to develop tumors after sc injection in Wistar rats. In five of five animals, RTC-R2 cells infected with mIL12 transducing adenovirus (AdCMVmIL12) in vitro failed to be tumorigenic in vivo in syngenic rats, whereas four of five animals developed tumors after injection of luciferase transducing adenovirus (AdCMVLuc)-infected cells. After intratumoral treatment with AdCMVmIL12 at 1 x 10(9) plaque-forming units per rat, 90% (26/29) of animals bearing small (<100 mm(3)) tumors were apparently cured. Larger tumors treated by injection of AdCMVmIL12 became significantly smaller than AdCMVLuc-treated animals, and growth stabilized. Challenge studies showed that only 3 of 28 animals previously treated and cured with AdCMVmIL12 developed a tumor after sc reinjection of RTC-R2 cells, whereas all animals developed tumors in naïve animals. Thus, AdCMVmIL12-treated animals developed long-term antitumor immunity. We also studied animals with two tumors, injecting virus in one. Tumors regressed at both sites in five of six animals after treatment of one tumor with AdCMVmIL12, and in the sixth animal one site tumor regressed and another tumor continued to grow. In AdCMVLuc-treated animals, both tumors regressed in only one animal, and the reminder continued to grow. To detect toxicity to liver and other tissues after administration of AdCMVmIL2, the vector was administrated intratumorally or iv at the dose of 2 x 10(9) plaque-forming units per rat. No change in behavior was observed in any of the treated animals. Rats were killed at different time after virus administration. An overt increase of spleen size was observed 7 d after infection in all animals treated with AdCMVmIL12. All animals given virus IV had some lymphocyte infiltration in the sinusoids and triads of the liver, whereas AdCMVmIL12 injected intratumorally did not cause this effect. Spleens of some virus-treated animals showed decreased white pulp, with apparently increased hematopoiesis. No specific changes were found in lungs and kidneys. Iv administration of AdCMVmIL12 induced a moderate increase of glutamic-oxalacetic transaminase and glutamic-pyruvic transaminase, whereas AdCMVmIL12 injected intratumorally did not. This study confirms the efficient antitumor activity of an adenovirus expressing mIL12 after in vivo delivery in an animal model and indicates the possibility of application to patients because of the low toxicity.

Genetic immunotherapy of established tumours with adenoviral vectors transducing murine interleukin-12 (mIL12) subunits in a rat medullary thyroid carcinoma model.

Interleukin-12 (IL12) is a heterodimeric cytokine that plays an important role in the development of cellular immunity. Studies have demonstrated antitumour activity after systemic administration of recombinant IL12. As with other cytokines, with increasing dosage and longer exposure, systemic toxicity is observed. To reduce systemic toxicity and obtain local production of IL12, we developed a replication defective adenovirus transducing two subunits of the murine IL12 (AdCMVmIL12) gene. Two separate cassettes, expressing the p35 or p40 subunit of mIL12, under the control of human cytomeglavirus immediate early promoter, were inserted into the early1 (E1) region of adenovirus 5. Biological activity of virally expressed mIL12 was demonstrated in vitro through its ability to induce proliferation of mouse ConA blast cells. Rat medullary thyroid carcinoma (MTC) cells infected with AdCMVmIL12 lost their tumorigenicity in their syngenic WAG/Rij rat hosts. Efficient antitumour activity was found after direct injection of the AdCMVmIL12 vector into rMTC tumours. After intratumoural treatment with AdCMVmIL12, 86% of tumour bearing animals were apparently cured, and almost all remaining tumours were stabilized. Challenge studies showed that most animals cured after the first treatment remained tumour free after reinjection of wild type rMTC cells, indicating that long-term antitumour immunity developed. This study demonstrates the construction of an adenoviral vector expressing a functional heterodimeric mIL12 and its efficient antitumour activity after in vivo delivery in an animal model of medullary thyroid carcinoma.

PERIPHERAL BLOOD LYMPHOCYTE SUBSET PROFILE OF YOUNG CHILDREN EXPERIENCING RECURRENT GASTROINTESTINAL INFECTIONS SIMULATES THAT OF ADULTS.

The cellular immune system, less mature at birth, undergoes significant developmental changes within the first few years of life. Lymphocyte subsets in healthy children are currently characterized by age-related standards. In order to determine the effect of antigenic exposure on cellular immune development, peripheral blood lymphocyte [PBL] subsets were studied in two populations of children of similar age and nutritional status;children belonging to a rural population [RP] (n=71) residing in close proximity to farm animals and children from an economically privileged urban population [UP] (n=63). In each population children studied included a group with an acute diarrheal episode [DE] with no overt dehydration and a healthy control group[C]. Using fluorescent monoclonal antibodies and flow cytometry the following distinct PBL subsets were identified: helper T cells;CD4, suppressor cytotoxic T cells;CD8, NK cells; CD56, NK cells and subset of suppressor cytotoxic T cells; CD57 and two subsets of helper T cells: “memory” cells;CD45RO CD4 and “naive” cells;CD45RA CD4. Children studied were age 6-36 months. Mean age, weight and height (expressed as% of 50th centile for age) did not differ among the two populations but a marked difference was noted in previous infectious episodes reported. Among RP children, 65% had suffered at least one episode of gastroenteritis within the previous 3 month period as compared to <10% of UP children and 15% in the RP group had suffered 2 or more episodes. Proportion of CD4 cells was similar in both RP and UP children.Among helper T cells, proportion of “memory” cells CD45RO CD4/CD4 was more than two fold higher in RP children [in both the DE and C groups 47.5 ± 2.8 and 46.8 ± 3.7,mean ± s error] as compared to UP children [19.0±1.2 and 18.6 ±1.8 in DE and C groups, respectively]. In UP children the proportion of CD45ROCD4 /CD4 correlated significantly with age [r=0.4], in RP children no correlation with age was observed.Proportion of CD8 cells was higher in RP children as compared to UP children;30.9 ±1.8 [DE] and 33.0 ± 2.4 [C] vs 20.4 ± 1.5 [DE] and 21.7 ± 0.8 [C] respectively. The proportion of NK cells, CD56 and CD57, was 2-3 fold higher in RP children;{CD56: 14.8 ± 2.0 [DE] and 17.9 ± 2.0[C], CD57: 9.1 ±1.0[DE] and 7.6 ±0.9 [C]} vs levels in UP children;{CD56: 6.5 ± 0.9[DE] and 7.1 ± 0.8 [C], CD57: 2.6 ± 0.7 [DE] and 1.9 ± 0.3 [C]}. Within each population PBL subsets did not differ between the healthy control group and those with acute diarrhea. We conclude that in young children exposure to gastrointestinal antigenic stimuli is a major factor affecting development of the cellular immune response. Young children who have experienced recurrent gastrointestinal infections have a PBL profile similar to that of adults.

Construction of a double recombinant adenovirus vector expressing a heterodimeric cytokine: in vitro and in vivo production of biologically active interleukin-12.

Interleukin-12 (IL-12) is a heterodimeric cytokine that plays an important role in the development of cellular immunity. Clinical applications for this lymphokine include resolution of infectious disease, cancer immunotherapy, and boosting cellular immunity in AIDS patients. When using IL-12 and other cytokines therapeutically, an approach designed to obtain localized cytokine expression would be beneficial, because this could reduce the problem of systemic toxicity. As a means of developing a suitable delivery vehicle for IL-12, we have produced double-recombinant adenovirus vectors containing the p35 subunit cDNA of murine IL-12 in early region 1 of adenovirus type 5 and the cDNA for p40 in early region 3 (AdmIL-12). Cell lines infected with AdmIL-12 produced up to 42,000 units of IL-12/10(6) cells per 24 hr. Biological activity of the virally expressed product was demonstrated in vitro through its ability to induce proliferation of phytohemagglutinin (PHA)-stimulated lymphoblasts and to stimulate natural killer (NK) activity in naive splenocytes. Mice injected intraperitoneally with these vectors displayed serum IL-12 levels that increased proportionately with the amount of virus administered. IL-12 production in vivo caused a dose-dependent increase in splenic and lung NK cell activity. This work represents the first demonstration of a double-recombinant adenovirus vector expressing a functional heterodimeric protein. The results of these studies support the use of AdmIL-12 as an efficient delivery vehicle for IL-12, and direct studies of its ability to modulate cellular immunity in vivo are currently underway.

Administration of Systemic or Local Interleukin-2 Enhances the Anti-tumor Effects of Interleukin-12 Gene Therapy

Interleukin- 12 (IL- 12) is a cytokine with a wide variety of immunorerogulatory activities. These include stimulation of interferon-γ production, cytolytic activity of natural killer (NK) cells and T-cell subsets, the development of cellular immunity, and induction of maturation of Th1 cells. IL-12 also has potent anti-tumor activity in vivo. In the present study the possibility of enhanced anti-tumor activity was examined using a combination of local IL-12 by cytokine gene therapy at the tumor site, combined with systemic or local IL-2 delivery. NIH 3T3 fibroblasts transfected with the genes for both subunits of IL-12, p35 and p40, were used as the source of IL-12 therapy producing 240 HLRU/106 cells/48 hr. In the first part of the study the effect of different regimens of systemic IL-2 delivery with local IL-12 administration on the size and growth rate of subcutaneous MCA-105 murine sarcoma was examined. Local IL-12 alone reduced the sizes of tumors after 32 days from 163 to 20.8 mm2 (P < 0.002). Adding the longer-acting polyethylene-glycol-modified II-2 (PEG IL-2; 30,000 IU) for 5 days prevented the development of tumors in all treated mice compared to 1/3 mice treated with PEG IL-2 alone and 3/6 mice with IL-12, but this was a highly toxic therapy and most of the animals died. Administration of 60,000 IU of IL-2 on Days 1-5 postinoculation of tumor, delivered with IL-12 gene therapy, reduced the tumor growth rate compared to animals treated with IL-2 alone (P < 0.02) or IL-12 (0.1). After 30 days the mean tumor size was 1.2 mm2 compared to 17.8 mm2 with IL-12 alone, 85.4 mm2 with low-dose IL-2 (P < 0.05), and 46.2 mm2 in controls (P < 0.03). When IL-2 was added later, on Days 6-10, the additive effect of low-dose IL-2 with local IL-12 was less significant. Mean tumor sizes were 38.4 and 55 mm2. High-dose IL-2 abrogated the additive effect of IL-12. Tumor size was 111.4 compared to 55 mm2 with IL-12 alone. In the second part of the study the effect of local IL-2 produced by a transfected MC-38 murine colon adenocarcinoma cell line, producing IL-2 coupled with IL-12 gene therapy, was examined. Tumor cells and IL-12-producing NIH3T3 fibroblasts were injected at a ratio of 1:3 or 1:6. After 40 and 32 days, respectively, tumor sizes with the combined treatment were 8.25 and 19.6 mm2 compared to 62.5 and 134.4 mm2 with IL-12 alone or 59.8 and 133 mm2 with IL-2 alone. In conclusion, local IL-12 produced at the tumor site during cytokine gene therapy when delivered with systemic or local low-dose IL-2 causes delayed tumor growth, when they are administered at the appropriate amounts and at the right time. The initial role of sequence, timing, and means of delivery may mimic the requirement for induction of an effective natural immune response.

Role of interferons and other cytokines in the regulation of the immune response.

Cytokines represent the major factors involved in the communication between T cells, macrophages and other immune cells in the course of an immune response to antigens and infectious agents. A number of studies on mouse and human T helper (Th) clones have recently provided extensive evidence for the existence of different activities exhibited by Th cells (called Th1 and Th2), which was apparently inferred from the profile of cytokine secretion. The Th1-type immune response is generally associated with IgG2a production and the development of cellular immunity, the Th2-type response with IgE production, eosinophils and mast cell production. This review focuses on the role of different cytokines produced by macrophages (especially interferons (IFNs), TNF-alpha, IL-10 and IL-12) or T cells (IFNs, IL-2, IL-4, IL-10, IL-13 and TGF-beta) in macrophage-T cell interactions and the cytokine relevance in the differentiation of Th cells towards the Th1 or Th2 type of immune response. Th1-derived cytokines (IFN-gamma, IL-2, TNF-alpha) favor macrophage activation, whereas the Th2 cytokines (IL-4, IL-10, IL-13) exhibit suppressive activities on macrophage functions. A key role in the differentiation towards the Th1-type response is now attributed to IL-12, a recently described cytokine produced mainly by macrophages. Its production can be upregulated by IFN-gamma and is inhibited by IL-10 and IL-4. All this emphasizes the importance of macrophage-cytokine interactions in determining the type of immune response. This article also aims to review recent data concerning the roles of IFNs alpha/beta (type I) and IFN-gamma (type II) in the regulation of the immune response. While there is much information on the regulatory effects of IFN-gamma (also called "immune IFN") on the immune response, little is so far known of the role of type I IFNs. These cytokines, originally described as simple antiviral substances, are now taken to be important regulators of the immune response. Recent data indicate that these molecules (especially IFNs-alpha) specifically promote the differentiation towards the Th1-type response. The stimulatory effects of IFN-alpha on the generation of the Th1-type response may be involved in its therapeutic effects in some human diseases, including early AIDS, hypereosinophilia and certain tumors.(ABSTRACT TRUNCATED AT 400 WORDS)

Toxicity and Immunogenic Properties of Liposomal form of Vipera Libetina Venom

AbstractThe incorporation of Vipera libetina venom into liposomes obtained from pure egg phosphatidyl choline by the reverse phase evaporation method decreases its toxicity by 3-fold - in mice LD50 for the native toxin is 2.22 mg/kg body weight and for the liposomal toxin 6.9 mg/kg. Subcutaneous injection of liposomal preparation into mice stimulates the development of cellular immunity and reproduces the reaction of the delayed-type hypersensitivity. It is. also, shown that after a single dose immunization of mice with liposomes containing 1xLD50 dose of the venom, the.titer.of antibodies increases at the early postinfection period and is maintained on high level longer than after the injection of the native venom. Thus, liposom.es can be succesfully used for antiserum production and protective immunization against Vipera libetina venom.