Development Of Specific Immune Response Research Articles

Correlation between salivary immunoglobulin A and interleukin-1beta in smokers with dental caries.

Introduction. Dental caries is one of the most common infectious diseases of the oral cavity, and is an inflammatory disease caused by several factors. Interleukin-1β (IL-1β) is a major mediator of acute inflammation and essential for the development of specific immune responses. The objective of this study was to assess the levels of secretory IgA (s-IgA) and IL-1β in the saliva of smokers with dental caries, and to discover the correlation between these parameters and dental caries. Methods. Saliva samples were collected from 30 smokers, age range 21-70 years, with dental caries, in addition to 18 healthy non-smoker volunteers, age range 21-65 years. s-IgA and IL-1β levels in the saliva samples were estimated by enzyme-linked immunosorbent assay (ELISA). Results. The mean saliva IgA levels between smokers with dental caries group and healthy subjects were not significantly different (p=0.077), while the saliva levels of IL-1β were higher in the smokers in dental caries group, with a significant difference of p<0.05. No significant associations were found between s-IgA and IL-1β levels, and other parameters such as age, sex, body mass index (BMI) and C-reactive protein (CRP) (p>0.05). There were highly positive associations and significant differences between IL-1β and CRP levels in the two groups under the study (p=0.006). Conclusions. Our study revealed a significant increase in IL-1β levels in saliva of smokers with dental caries, and a positive association between IL-1β levels and caries disease. There is no significant relationship between elevated IL-1β levels and s-IgA in smokers with dental caries.

Correlation between salivary immunoglobulin A and interleukin-1beta in smokers with dental caries

Introduction. Dental caries is one of the most common infectious diseases of the oral cavity, and is an inflammatory disease caused by several factors. Interleukin-1β (IL-1β) is a major mediator of acute inflammation and essential for the development of specific immune responses. The objective of this study was to assess the levels of secretory IgA (s-IgA) and IL-1β in the saliva of smokers with dental caries, and to discover the correlation between these parameters and dental caries. Methods. Saliva samples were collected from 30 smokers, age range 21–70 years, with dental caries, in addition to 18 healthy non-smoker volunteers, age range 21–65 years. s-IgA and IL-1β levels in the saliva samples were estimated by enzyme-linked immunosorbent assay (ELISA). Results. The mean saliva IgA levels between smokers with dental caries group and healthy subjects were not significantly different (p=0.077), while the saliva levels of IL-1β were higher in the smokers with dental caries group, with a significant difference of p&lt;0.05. No significant associations were found between s-IgA and IL-1β levels, and other parameters such as age, sex, body mass index (BMI) and C-reactive protein (CRP) (p&gt;0.05). There were highly positive associations and significant differences between IL-1β and CRP levels in the two groups under the study (p=0.006). Conclusions. Our study revealed a significant increase in IL-1β levels in saliva of smokers with dental caries, and a positive association between IL-1β levels and caries disease. There is no significant relationship between elevated IL-1β levels and s-IgA in smokers with dental caries.

Subcutaneous injection of an immunologically tolerated protein up to 5 days before skin injuries improves wound healing.

Oral tolerance blocks the development of specific immune responses to proteins ingested by the oral route. One of the first registries of oral tolerance showed that guinea pigs fed corn became refractory to hypersensitivity to corn proteins. Mice fed with chow containing corn are tolerant to zein, and parenteral injection of zein plus adjuvant blocks immunization to unrelated proteins injected concomitantly and reduces unspecific inflammation. Extensive and prolonged inflammatory infiltrate in the wound bed is one of the causes of pathological wound healing. Previous research shows that intraperitoneal injection of zein concomitant with skin injuries reduces the inflammatory infiltrate in the wound bed and improves wound healing. Herein, we tested if one subcutaneous injection of zein before skin injury improves wound healing. We also investigated how long the effects triggered by zein could improve skin wound healing. Mice fed zein received two excisional wounds on the interscapular skin under anesthesia. Zein plus Al(OH)3 was injected at the tail base at 10 min, or 3, 5, or 7 days before skin injuries. Wound healing was analyzed at days 7 and 40 after injury. Our results showed that a zein injection up to 5 days before skin injury reduced the inflammatory infiltrate, increased the number of T-cells in the wound bed, and improved the pattern of collagen deposition in the neodermis. These findings could promote the development of new strategies for the treatment and prevention of pathological healing using proteins normally found in the common diet.

Adjuvant-mediated enhancement of the immune response to HIV vaccines.

Protection from human immunodeficiency virus (HIV) acquisition will likely require an effective vaccine that elicits antibodies against the HIV-1 envelope glycoproteins (Envs), which are the sole target of neutralizing antibodies and a main focus of vaccine development. Adjuvants have been widely used to augment the magnitude and longevity of the adaptive immune responses to immunizations with HIV-1 Envs and to guide the development of specific immune responses. Here, we review the adjuvants that have been used in combination with HIV-1 Envs in several preclinical and human clinical trials in recent years. We summarize the interactions between the HIV-1 Envs and adjuvants, and highlight the routes of vaccine administration for various formulations. We then discuss the use of combinations of different adjuvants, the potential effect of adjuvants on the elicitation of antibodies enriched in somatic hypermutation and containing long complementarity-determining region 3 of the antibody heavy chain, and the elicitation of non-neutralizing antibodies.

Original Research: Parvovirus B19 infection in children with sickle cell disease in the hydroxyurea era.

Parvovirus B19 infection causes transient aplastic crisis in sickle cell disease (SCD) due to a temporary interruption in the red blood cell production. Toxicity from hydroxyurea includes anemia and reticulocytopenia, both of which also occur during a transient aplastic crisis event. Hydroxyurea inhibits proliferation of hematopoietic cells and may be immunosuppressive. We postulated that hydroxyurea could exacerbate parvovirus B19-induced aplastic crisis and inhibit the development of specific immune responses in children with SCD. We conducted a retrospective review of parvovirus B19 infection in 330 children with SCD. Altogether there were 120 known cases of aplastic crisis attributed to parvovirus B19 infection, and 12% of children were on hydroxyurea treatment during the episode. We evaluated hematological and immune responses. Children with HbSS or HbSβ(0)-thalassemia treated with hydroxyurea, when compared with untreated children, required fewer transfusions and had higher Hb concentration nadir during transient aplastic crisis. Duration of hospital stays was no different between hydroxyurea-treated and untreated groups. Children tested within a week following aplastic crisis were positive for parvovirus-specific IgG. Immune responses lasted for the duration of the observation period, up to 13 years after transient aplastic crisis, and there were no repeat aplastic crisis episodes. The frequencies of parvovirus-specific antibodies in all children with SCD increased with age, as expected due to the increased likelihood of a parvovirus exposure, and were comparable to frequencies reported for healthy children. Approximately one-third of children had a positive parvovirus B19-specific IgG test without a documented history of transient aplastic crisis, and 64% of them were treated with hydroxyurea. Hydroxyurea may reduce requirements for blood transfusions and may attenuate symptoms during transient aplastic crisis episodes caused by parvovirus B19 infections. Children with SCD, whether treated or untreated with hydroxyurea, generate sustained and protective parvovirus B19-specific immune responses.

Towards a Preventive Strategy for Toxoplasmosis: Current Trends, Challenges, and Future Perspectives for Vaccine Development.

With its facultative ability to induce various types of infection in its hosts, Toxoplasma gondii remains a fascinating and enigmatic pathogen. As a parasite, despite its primitive unicellular structure, it possesses a highly sophisticated arsenal of invasive and defensive tools. Toxoplasmosis has gained widespread significance as a zoonotic disease capable of inducing severe illnesses in humans and drastic economic losses in the veterinary field. Although around a third of the world's population is infected with Toxoplasma gondii, immunocompromised people, pregnant women, and neonates are more vulnerable to the most severe forms of the disease. Hence, development of a preventive strategy is urgently needed to combat T. gondii infection in both humans and animals. Successful triggering of host immune responses and development of specific immune responses against the different strains and antigens of T. gondii has encouraged researchers to focus on vaccination as a feasible preventive control strategy against toxoplasmosis. In the last few years, vaccine development against T. gondii infections has seen great advances and achievements being made at the research level and, to a lesser extent, in veterinary applications. Currently, only one live attenuated vaccine is available for reducing abortions and fetal losses in pregnant ewes. Otherwise, researchers have investigated numerous classes of vaccine, including live attenuated, recombinant subunit, and vectored. In this chapter we discuss the most commonly investigated vaccines against toxoplasmosis, recombinant DNA and protein vaccines, with special focus on their methodologies and mechanisms of action.

Characterization of the in situ immunological responses to vaccine adjuvants

Adjuvants are included with many inactivated and some modified live vaccines to enhance immune responses to specific antigens. While early vaccines relied exclusively upon aluminum salts, still the major adjuvant used in human vaccines, other adjuvant products are used in veterinary medicine. In addition to enhancing antigen presentation, adjuvants can also enhance the development of specific immune responses. Thus, alum adjuvants often preferentially stimulate humoral immune responses. By contrast, lipid-based adjuvants are often more effective at stimulating cell-mediated immune responses. Metastim® is a lipid-based adjuvant reported to elicit both humoral and cellular immune responses, though the mechanism responsible for this activity remains unclear. In this study, we compared the ability of equine influenza virus vaccines containing either saline or Metastim® or an aluminum phosphate adjuvant to stimulate antigen presenting cell function in vivo. Six ponies were intradermally inoculated with inactivated equine influenza (KY97) mixed with either adjuvant or saline. Multiple sites were injected so that biopsies could be collected at different times post injection. The 4mm punch biopsies were formalin-fixed, paraffin-embedded, and stained with hematoxylin and eosin (H&E). Total RNA was isolated from 2mm punch biopsies for the determination of gene expression by real-time PCR. H&E staining revealed a variety of cells recruited to the injection sites, including lymphocytes, neutrophils, eosinophils and macrophages. Real-time PCR analysis of the injection site confirmed this cellular infiltration and identified increased expression of activation markers. Both vaccines also stimulated gene expressions of pro-inflammatory cytokines. The vaccine containing Metastim® elicited significantly higher gene expression of interferon-γ, IL-12, CD4and CD83 compared to alum (p<0.05). While the greater induction of IFNγ-related gene expression indicates that Metastim® can elicit Th-1 immune responses more effectively than the aluminum salt, there was also evidence of Th2 cytokine induction.

Antigen-specific lymphocyte proliferation as a marker of immune response in guinea pigs with sustained Helicobacter pylori infection.

Helicobacter pylori (H. pylori) bacteria are human pathogens causing symptomatic gastritis, peptic ulcer or gastric cancer. Little is known about the kinetics of immune responses in H. pylori infected patients because the initial moment of infection has not been identified. Various animal models are used to investigate the immune processes related to H. pylori infection. In this study we checked whether H. pylori infection in guinea pigs, mimicking natural H. pylori infection in humans, resulted in the development of specific immune responses to H. pylori antigens by measuring the proliferation of lymphocytes localized in mesenteric lymph nodes, spleen and peripheral blood. The maturity of macrophages and cytokines, delivered by monocyte-macrophage lineage or lymphocytes, were considered as mediators, which might influence the lymphocyte blastogenic response. The obtained results showed the activation of T cells localized in mesenteric lymph nodes by H. pylori antigens in H. pylori infected guinea pigs four weeks postinfection. The blastogenic activity of lymphocytes was shaped by their interaction with antigen presenting cells, which were present in the cell cultures during the whole culture period. Moreover, the balance between cytokines derived from adherent leukocytes including interleukin 8--IL-8 as well as interferon gamma--IFN-γ, and transforming growth factor beta--TGF-β delivered by lymphocytes, was probably important for the successful proliferation of lymphocytes. The H. pylori specific lymphocytes were not propagated in peripheral blood and spleen of H. pylori infected animals. The modulation of immunocompetent cells by H. pylori antigens or their different distribution cannot be excluded.

Effects of tamoxifen on estrogen receptor-α level in immune cells and humoral specific response after immunization of C3H/He male mice with syngeneic testicular germ cells (TGC)

Estrogens and estrogen receptors (ERs) are potent regulators of the immune response. Disruption of ERα or modulation of its function by selective ligands during experimental autoimmune conditions changes the course of disease by influencing specific humoral and cellular responses. However, it is not known whether fluctuation in the ERα level and the variable accessibility to its ligands in immune cells influence the development of specific immune responses against auto-antigens. This study was designed to evaluate the expression level of ERα in splenic immune cells and the specific humoral immune response in male C3H/He/W mice immunized with syngeneic testicular germ cells (TGC) in the presence of tamoxifen. Levels of ERα protein in immune cell subpopulations of immunized mice (assessed by flow cytometry) increased in MHCII+CD86+, MHCII+CD86− , F4/80+MHCII+, immature macrophages (F4/80+/MHCII− ), and CD3+CD4+ T cells. Addition of tamoxifen decreased the level of ERα in MHCII+CD86+, MHCII+CD86− , F4/80+MHCII+, immature macrophages (F4/80+/MHCII− ), and the CD19+CD3− cell subpopulation of immunized mice. Therefore, immunization with syngeneic antigen and tamoxifen treatment evoked cell-type specific changes in the level of ERα. Irrespective of tamoxifen treatment the humoral response in immunized animals toward TGCs was similar, suggesting that modulation of the level of ERα in immune cells is not directly related to specific auto-antibody production.

Effects of prenatal diesel exhaust inhalation on pulmonary inflammation and development of specific immune responses

There is increasing evidence that exposure to air pollutants during pregnancy can result in a number of deleterious effects including low birth weight and the incidence of allergic asthma. To investigate the in utero effects of DE exposure, timed pregnant BALB/c mice were exposed to 0, 0.8 or 3.1 mg/m 3 of DE during gestation days (GD) 9 to GD 18. The number of successful pregnancies was 15/20 in the air controls and 10/20 in each of the diesel exposures. Immune function in the 6-week-old offspring as determined by development of delayed type hypersensitivity (DTH) reactions to bovine serum albumin (BSA), antibody titers to injected sheep red blood cells (SRBC), splenic T cells expressing CD45 +CD3 +CD8 + and CD3 +CD25 +, and mRNA expression of TNF-α, TLR2, SP-A, TGF-β and Foxp3 in the lung were not affected by prenatal DE exposure. On the other hand, lung TLR4 mRNA expression, the number of neutrophils in the bronchoalveolar lavage fluid (BALF) and splenic T cells expressing CD45 +CD3 +CD4 + and CD4 +CD25 + were differentially affected depending on the DE concentration and gender. When additional groups of mice were sensitized and challenged via the respiratory tract with ovalbumin to induce allergic airway inflammation, female mice had higher protein levels in the BALF compared to males and this was reduced by prenatal exposure to either concentration of DE. No other changes in allergen-induced immunity, lung function or severity of inflammation were noted. Collectively, the results show that in utero exposure to DE altered some baseline inflammatory indices in the lung in a gender-specific manner, but had no effect on development of specific immune responses to experimental antigens, or the severity of allergic lung inflammation.

Pasteurella multocida toxin (PMT) activates RhoGTPases, induces actin polymerization and inhibits migration of human dendritic cells, but does not influence macropinocytosis

Dendritic cells (DCs) are considered as one of the principal initiators of immune responses. In their immature state, they migrate into peripheral tissue in order to uptake antigen and to patrol for danger signals. Upon maturation, they acquire the ability to migrate to the lymph nodes and present the captured antigens to T cells in order to direct the development of specific immune responses. There is evidence that microbial compounds interfere with proper functions of DCs in order to block innate and specific immunity. Here we characterized the influence of Pasteurella multocida toxin (PMT) on monocyte-derived DCs. Using pull-down assays with recombinant rhotekin or p21-activated kinase, we demonstrated the activation of RhoGTPases by PMT in DCs. Moreover, PMT induced changes in DC morphology and actin polymerization, impaired chemotaxin-induced actin re-organization and inhibited their migration response. However, macropinocytosis was not influenced by PMT. In summary, these data indicate that PMT inhibits proper function of the motility machinery in DCs, which might limit the development of adaptive immune surveillance during infection with Pasteurella multocida.

Relevance of immune response against resident and not resident commensal strains for the definition of strategies of probiotic supply in the diet of weaning pigs

RiassuntoImportanza della risposta immunitaria nei confronti di commensali residenti e non, per la definizione di strategie d’impiego di probiotici nella dieta del suino in svezzamento. Con l’impiego di probiotici spesso si osserva una maggiore risposta umorale, ma non è documentato se l’animale d’allevamento reagisca anche contro lo stesso probiotico. Sono stati analizzati campioni di sangue e saliva raccolti in due prove di somministrazione di probiotici a suini in svezzamento: A) Lactobacillus rhamnosus GG, non tipico del suino; B) Lactobacillus sobrius 001T, isolato dal suino. Anticorpi probiotico specifici sono stati riscontrati nel siero dei soggetti prima del trattamento (prova A) e nei gruppi di controllo, nonostante l’assenza di DNA ceppo-specifico nel loro contenuto intestinale (prova A e B). Utilizzando un test ELISA su siero o saliva preincubati con uno o l’altro dei lattobacilli, si è visto che ciascuno di questi lega parte delle IgA specifiche per l’altro. Quindi batteri con differente affinità per il suino possono presentare attività immunologia crociata reciproca. Nella definizione dell’impiego di un probiotico nella dieta del suinetto si deve valutare con attenzione la presenza di anticorpi già attivi prima della sua somministrazione.

Parvovirus B19

B19 parvovirus is transmitted via the respiratory route. Its target cells are the erythroid precursors BFU-E, CFU-E. Infection of such cells result in bone marrow suppression, which can be inapparent in normal individuals but may result in transient aplastic crisis in subjects with chronic hemolytic anaemia. Humoral response contributes to the end of infection explaining the occurence of chronic anaemia in patients with impaired immune response. The development of specific immune response correlates with the appearance of erythematous rash and arthropathies. Its association with systemic diseases remains to define. No specific treatment is available ; transfusion and administration of gammaglobulins will be used respectively in patients with acute or chronic anaemias.

Lymphoid hyperplasia, CD45RBhigh to CD45RBlow T-cell imbalance, and suppression of Type I diabetes mellitus result from TNF blockade in NOD-->NOD-scid adoptive T cell transfer.

Sustained antibody-mediated inhibition of tumor necrosis factor (TNF) activity offers protection against Type I (insulin-dependent) diabetes mellitus in non-obese diabetic (NOD) mice. The mechanism of this effect, however, has remained obscure: TNFalpha might be required for the development of specific immune responses to islet antigens or it could directly participate in destruction of beta cells. In this study, autoimmune destruction of beta cells was initiated in NOD-severe combined immunodeficient (scid) mice by transfer of NOD splenic T-cells to induce diabetes. The blockade of TNFalpha activity was achieved during a narrow window of time after transfer. Transient inhibition of TNFalpha greatly reduced the number of islet lymphocytes and the incidence of diabetes in recipients of prediabetic NOD spleen cells. Protection extended beyond the interval of effective TNF blockade. Furthermore, the protective effect was only observed if cells were obtained from 6-week-old donors. The suppression of autoimmunity was reversible in the context of adoptive transfer as indicated by the transfer of splenocytes from the primary recipient to a second NOD-scid host led to a diabetic outcome. The blockade of TNFalpha was accompanied by a considerable increase in spleen size and doubling of the total splenocyte count, suggesting that TNFalpha might normally eliminate a transplanted T-cell subset within the recipients. Further analysis showed an increase in the absolute count of CD4 + T cells and pronounced distortion of the CD45RBhigh to CD45RBlow ratio, with a relative augmentation in the CD45RBlow count in the spleen. TNFalpha appears to regulate the number and subtype distribution of a transplanted T cell population.

Generation of Antigen-Specific Th2 Cells from Unprimed Mice In Vitro: Effects of Dexamethasone and Anti-IL-10 Antibody

We describe a system for the in vitro production of Ag-specific mouse CD4 cell lines from unprimed mice. Purified CD4+ CD45RB(high) T cells were exposed to Ag-pulsed accessory cells in serum-free medium for 24 h; cultured in the absence of Ag and in the presence of serum, IL-2, dexamethasone, and Abs to IL-10 for an additional 4 days; and then re-exposed to the original sensitizing Ag. The presence of dexamethasone and Abs to IL-10 during the initial expansion stage appeared to be critical for the ability of the stimulated and expanded T cells to respond to restimulation with the same Ag. Repeated cycles of in vitro stimulation led to increased specificity for the sensitizing Ag (in the current case, pigeon cytochrome c), a decline in production of IL-2 and IFN-gamma, and increased production of IL-4, IL-5, and IL-10. This culture protocol provides a test system for exploration of factors that regulate the conversion of naive cells to memory cells and the development of specific immune responses to protein Ags. The data are consistent with models that implicate glucocorticoids as regulators of immune response specificity.

The extent of early viral replication is a critical determinant of the natural history of simian immunodeficiency virus infection.

Different patterns of viral replication correlate with the natural history of disease progression in humans and macaques infected with human immunodeficiency virus type 1 (HIV-1) and simian immunodeficiency virus (SIV), respectively. However, the viral and host factors influencing these patterns of viral replication in vivo are poorly understood. We intensively studied viral replication in macaques receiving identical inocula of SIV. Marked differences in viral replication patterns were apparent within the first week following inoculation, a time prior to the development of measurable specific immune effector responses to viral antigens. Plasma viral RNA levels measured on day 7 postinoculation correlated with levels measured in the postacute phase of infection. Differences in the susceptibility of host cells from different animals to in vitro SIV infection correlated with the permissiveness of the animals for early in vivo viral replication and hence with the postacute set point level of plasma viremia. These results suggest that host factors that exert their effects prior to full development of specific immune responses are critical in establishing the in vivo viral replication pattern and associated clinical course in subjects infected with SIV and, by extension, with HIV-1.

Critical contribution of beta chain residue 57 in peptide binding ability of both HLA-DR and -DQ molecules.

Position 57 in the beta chain of HLA class II molecules maintains an Asp/non-Asp dimorphism that has been conserved through evolution and is implicated in susceptibility to some autoimmune diseases. The latter effect may be due to the influence of this residue on the ability of class II alleles to bind specific pathogenic peptides. We utilized highly homologous pairs of both DR and DQ alleles that varied at residue 57 to investigate the impact of this dimorphism on binding of model peptides. Using a direct binding assay of biotinylated peptides on whole cells expressing the desired alleles, we report several peptides that bind differentially to the allele pairs depending on the presence or absence of Asp at position 57. Peptides with negatively charged residues at anchor position 9 bind well to alleles not containing Asp at position 57 in the beta chain but cannot bind well to homologous Asp-positive alleles. By changing the peptides at the single residue predicted to interact with this position 57, we demonstrate a drastically altered or reversed pattern of binding. Ala analog peptides confirm these interactions and identify a limited set of interaction sites between the bound peptides and the class II molecules. Clarification of the impact of specific class II polymorphisms on generating unique allele-specific peptide binding "repertoires" will aid in our understanding of the development of specific immune responses and HLA-associated diseases.

Distinct antigen-induced cytokine pattern upon stimulation with antibody-complexed antigen consistent with a Th1 → Th2-shift

The consequences of complexing an antigen with specific antibodies upon the antigen-induced immune response were studied with respect to secretion of interleukin-2 (IL2), interleukin-6 (IL6), interleukin-10 (IL10) and interferon-gamma (IFN gamma). We found that the tetanus toxoid antigen-induced cytokine pattern was mainly dependent on the antigen/antibody ratio. While tetanus toxoid antigen alone induced a typical Th1-like cytokine pattern with high levels of IL2 and IFN gamma, equivalent or antibody-excess immune complexes induced a marked secretion of IL6 and IL10 while failing to induce IL2 and IFN gamma secretion. As the cytokine pattern plays a crucial role in the development of specific immune responses towards infectious agents, our results indicate that immune complexes--typically occurring during the course of chronic infectious diseases--may play an important role in the modulation of immune responses. Since a shift from Th1 to Th2 immune responses has been discussed as a pathogenetic factor in HIV-induced immunodeficiency, the role of circulating immune complexes as a possible cause for this shift should be considered.

Inhibition of growth of Trypanosoma brucei parasites in chronic infections.

The growth of Trypanosoma brucei parasites in chronic infections was investigated by superimposing upon chronic infections, secondary infections in which all parasites expressed the same variable antigen type (VAT). The fate of trypanosomes in secondary infections could then be monitored using the VAT as a marker to discriminate cells in primary and secondary infections and thus enable growth to be observed separately from its interactions with antigenic variation on the part of the parasite and specific immune responses of the host. Our results show that as an infection proceeds, the growth rate is progressively inhibited in mice and sheep, suggesting that inhibition is a general feature of chronic infections. Inhibition was not specific to either the stock or the VAT of the trypanosome, but the degree of inhibition did vary between stocks. Inhibition appeared to be mediated by a lowering of the rate of replication of 'slender'-form parasites rather than by an increase in either the rate of differentiation from dividing slender to non-dividing 'stumpy' forms or the mortality caused by non-specific immune mechanisms. Evidence indicated that the development of specific immune responses to non-variant parasite antigens was also unlikely. These data constitute, we believe, the first evidence for negative regulation of growth in vivo, which may be an important determinant of the virulence of trypanosome infections.

Immunotherapeutic strategies targeting rheumatoid synovial T-cell receptors by DNA inoculation.

Immunotherapy against autoreactive T-cell receptors (TCRs) has been reported to have promise in several animal models of autoimmune diseases. Facilitated DNA inoculation has many potential advantages as a modality for development of specific immune responses. Specifically, this technology is able to deliver exogenous antigens for processing via both the endogenous pathway, with subsequent presentation by class-I major histocompatibility (MHC) antigens, and the exogenous pathway, with subsequent presentation by class-II MHC antigens. This allows for induction of both arms of the cellular immune system. These cellular immune responses may be particularly important in targeting and controlling pathogenic cell populations. The application of this technology to the treatment of human autoimmune diseases depends on the availability of readily manipulated systems for the evaluation of specific interventions. Here we report the full length cloning and expression of TCRs from rheumatoid arthritis synovial tissue. These were developed by recombinant polymerase chain reaction, cloning and retroviral transduction into a TCR-alpha/beta-negative murine T-cell hybridoma. Reconstitution of CD3 expression was confirmed by flow cytometry. Similar constructs have been developed for TCR-based immunotherapy by facilitated inoculation of DNA intramuscularly. Preliminary analysis of immune responses in mice indicates that these constructs elicit anti-TCR responses. These studies indicate the ability to reconstitute expression of potentially autoreactive human TCRs in a model system wherein specific immune responses elicited against these TCRs by various immunogens can be evaluated.