Increased Lymphocyte Proliferation Research Articles

Immune response impairment, genotoxicity and morphological transformation induced by Taenia solium metacestode

In chronic helminthic infections such as cysticercosis, where the parasites live for years, profound modulation of the host immune response has been reported. To evaluate the genotixicity of a drug used to treat cysticercosis, we observed the occurence of genetic damage in cultured lymphocytes from cysticercotic swine and patients who had not been exposed to the drug. The human lymphocytes also showed a slower proliferation. These data suggested that the disease itself was promoting genetic damage in host lymphocytes which, in part, could explain the retardation of the lymphocyte proliferation observed in cysticercotic patients. Pigs infected with Taenia solium cysticerci showed an increased lymphocyte proliferation for 6–8 weeks post infection, followed by an impaired proliferation after this period. Significant induction of sister-chromatid exchanges was also observed in lymphocytes from infected pigs after the 6th week post infection. Additionally, it was found that a factor secreted by the cysticerci morphologically transformed primary fibroblasts in culture. The results strongly suggest that the parasite produces genetic instability in the host cells, which would result in immunosuppression and malignant transformation of target cells.

Cellular immunity, HLA-class I antigens, and family history of psychiatric disorder in endogenous psychoses

We found an increased lymphocyte proliferation after stimulation with an antigen “cocktail” in 49 schizophrenic patients and 37 patients suffering from affective psychosis, compared with 45 healthy control subjects. On the basis of this and other findings such as increased numbers of CD3 + and CD4 + cells, an increased ration of CD4 +/CD8 + cells, and a reduced level of suppressor cell activity in schizophrenia and endogenous depression, we investigated the influence of the human leukocyte antigen-Class I (HLA-A, HLA-B, HLA-C) system on the altered immune function and evaluated the relationship to immune function of a family history of psychiatric disorders. A cluster analysis of cases with regard to the HLA-Class I antigens was first performed in a group of 133 healthy control subjects, and two immunogenetically different clusters were found; then 86 patients (49 schizophrenics, 37 affective psychoses) for whom immune functional data were available were assigned to the two HLA-I clusters that had been determined in the control subjects. Analyses of variance (ANOVAs) showed no differences in immune function between the two clusters. With respect to the cluster assignment and the family history of psychiatric diseases, a two-way ANOVA revealed significant differences in the lymphocyte response to the antigen cocktail, in the number of CD8 + cells, and in one suppressor cell assay. When patients were compared by ANOVA on the basis of family history of psychiatric disorder, patients with a positive family history showed a significantly higher number of CD4 + cells and a higher CD4 +/CD8 + ratio. Moreover, certain HLA genes, especially HLA-A1, HLA-B8, HLA-B16, and HLA-C2 seemed to be related to the immune function and/or to the immune function and the family history.

Childhood Idiopathic Thrombocytopenic Purpura: Experience at King Khalid University Hospital, Riyadh

Forty-nine children (30 boys and 19 girls) with idiopathic thrombocytopenic purpura (ITP) seen at King Khalid University Hospital (KKUH) Riyadh, during a 7-1/2 year period were retrospectively reviewed with regard to their clinical characteristics, management, and outcome. The age of onset of the disease ranged from 8 months to 11 years with a mean of 4.26 years. Twenty-seven cases presented as acute ITP while 22 cases presented as chronic ITP. The clinicopathological features and response to treatment of the cases were essentially similar to findings in other parts of the world. In a search for a predictor of chronic disease, the platelet counts at four weeks and three months after diagnosis were found to be a significant factor for prediction of chronicity of ITP. If the platelet counts are less than 100x10(9)/L during these periods, the risk of chronic ITP is increased and vice versa. There was, however, no correlation in our patients between duration of symptoms prior to presentation and outcome of the disease as has been reported by investigators in Europe and Australia.

Allergic contact reaction to dexpanthenol: lymphocyte transformation test and evidence for microsomal-dependent metabolism of the allergen.

In a patient with contact dermatitis, dexpanthenol was found to be the causative allergen. There was a positive reaction to dexpanthenol on patch testing. Controls did not show any positive reactions to dexpanthenol on patch testing. Additionally, an LTT was performed. After preincubation with dexpanthenol-modified microsomes, we observed an increase in lymphocyte proliferation to dexpanthenol, in comparison to dexpanthenol without microsomes, suggesting that microsomal metabolism plays a rôle in the pathogenesis of dexpanthenol sensitization, because microsomes are known to possess drug metabolizing enzymes such as cytochrome P450.

Psychosocial factors and immune senescence in the aged primate.

With increasing age, old animals and humans show decreases in a number of immune responses indicative of the process of immune senescence. Our studies investigated whether social companionship, as a potentially positive psychological intervention, would increase lymphocyte proliferation and natural killer cell activity in the aged nonhuman primate. Contrary to our initial hypothesis, social stimulation resulted in decreased immune responses in old monkeys. With specific modifications of the housing conditions it was possible to prevent these decreases in immune responses from occurring, but social companionship still failed to enhance immune responses in the aged monkey.

Immunity to Pasteurella multocida in Protein-Deficient Chickens

Studies were conducted to determine the effects of dietary protein restriction on the humoral immunity (HI) and cell-mediated immunity (CMT) of chickens. New Hampshire chickens were separated into two dietaiy treatment groups: basal, containing 3,200 kcal/kg and 21% protein; or protein restricted (PR), containing 3,200 kcal/kg and 7% protein. In studies involving HI, half of the birds in each dietary treatment were vaccinated against fowl cholera at 4 and 8 wk of age. Blood samples were collected weekly beginning at 4 wk of age. Overall, unvaccinated birds had lower titers than vaccinated birds and PR groups generally showed lower titers than basal groups. All birds were challenged by palatine cleft inoculation of live, virulent Strain X-73 of Pasteurella multocida. The vaccinated PR group survived live challenge as well as the vaccinated basal group, but all unvaccinated birds died as a result of the challenge, regardless of antibody titer.In studies involving CMI, half of the birds in each dietary treatment were vaccinated at 5 wk of age. At 2 to 3 wk postvaccination, representative birds from each treatment were bled for total and differential blood counts. Also, birds were sacrificed and spleen cells collected. Cells were cultured in Roswell Park Memorial Institute (RPMI) medium with phytohemagglutinin-M (PHA-M), sonicated P. multocida (X-73), or RPMI only. The PR birds had significantly decreased numbers of lymphocytes, as well as an overall decrease in total white blood cell counts. Within dietary treatments, vaccinated birds tended to have higher numbers of white blood cells, but (he differences were only significant for the PR groups in Experiment 4. The PR diet suppressed proliferation of splenic cells stimulated with PHA-M, and vaccination significantly increased lymphocyte proliferation in response to sonicated P. multocida, Strain X-73.

Immunotherapy with Mycobacterium vaccae as an adjunct to chemotherapy in the treatment of pulmonary tuberculosis

47 patients with adult-type pulmonary tuberculosis attending the Chest Diseases Hospital in Kuwait were given a single injection of 10 9 irradiation-killed M. vaccae after 1 month of a 9-month course of chemotherapy. The patients were followed-up for 3 more months in double blind comparison with 65 patients given an injection of saline (placebo). The immunotherapeutic injection produced a small local lesion in 44/47 patients, 18 of which ulcerated and produced small scars. Immunotherapy made no measurable difference to the bacteriological, biochemical, haematological, or radiological parameters measured. However it was associated with significantly improved weight gain, reduced size of skin test response to Tuberculin, increased lymphocyte proliferation to common mycobacterial antigens, and increased antibody levels to mycobacterial antigens. The changes in skin test and LTT responses were related and occurred in 29% of patients whose recognition of common mycobacterial antigens returned to normal. The remaining patients did not differ in these respects from those receiving placebo. The proportion of patients whose responses were improved was very similar to that achieved using the same immunotherapeutic agent in a group of treated multibacillary leprosy patients.

Effect of Physiological Concentrations of Calcitriol on Lymphocyte Proliferation in Normal Subjects and in Patients with Renal Failure

Specific receptors for calcitriol (1,25-dihydroxyvitamin D) have been found in immune cells, such as monocytes and activated lymphocytes, suggesting that calcitriol may play an immunoregulatory role. In fact, a marked increase in lymphocyte proliferation has been reported after treating hemodialyzed patients with 1 alpha-hydroxyvitamin D3, a precursor of calcitriol. We have studied in vitro the effect of calcitriol depletion and calcitriol addition on the phytohemagglutinin-induced mitogenesis of peripheral blood mononuclear cells from 14 healthy subjects and 8 hemodialyzed patients. The calcitriol depletion of culture medium did not modify cell proliferation. The addition of calcitriol in concentrations about the physiological range (10(-11) M) induced a small, marginally significant, 11% increase in the proliferation of lymphocytes from hemodialysis patients. Supraphysiological concentrations (10(-9)-10(-7) M) induced a marked inhibition (up to 60% of control values) of cell mitogenesis, both in patients and in healthy subjects. These results suggest that the increase in lymphocyte proliferation observed in vivo after treatment with calcitriol precursors is not mediated by a direct effect of calcitriol on circulating mononuclear cells.

Human cellular immune responses to Bordetella pertussis infection.

We have compared the responses of peripheral blood leucocytes from three groups (i) patients suffering from pertussis (whooping cough), (ii) clinical staff caring for those patients and laboratory staff working with Bordetella pertussis, and (iii) staff with no known recent contact with B. pertussis. In vitro stimulation with filamentous haemagglutinin (FHA) caused significant increases in proliferation of only the patient group's lymphocytes. In vitro stimulation with pertussis toxin (PT) caused a large increase in proliferation of lymphocytes from all three groups and in the patient group the increase in proliferation was related to the dose of PT. Interleukin 2 (IL-2) production by leucocytes from all three groups was significantly increased following challenge with FHA or PT. The increases in IL-2 production were greatest in lymphocytes from patients with pertussis. Challenge with toxoided pertussis toxin had no effect on either proliferation or IL-2 production in any of the groups.

Human Alveolar Macrophage Suppression of Lymphocyte Proliferation: Accessory Characteristics for the Generation and Functional Expression of Con A-induced Suppressor Cells

Human alveolar macrophages (AM) provide less accessory support for mitogen- and antigen-stimulated lymphocyte proliferation than do autologous blood-derived macrophages (BM). This is at least in part due to suppression mediated by AM, but the mechanism of such suppression is not understood. To determine whether AM-mediated suppression is related to AM interaction with suppressor lymphocytes (Ts), we examined the accessory cell function of both AM and BM for the generation and functional expression of Ts induced by concanavalin A (Con A). The data indicate that human AM are equivalent to BM for the generation of Con A-induced Ts, but AM mediate less suppression of Con A-induced Ts, once generated, than do BM. Addition of indomethacin did not increase lymphocyte proliferation when AM served as accessory cells. Supernatant fluids of Con A-exposed AM promoted greater proliferation of human T-lymphocytes and mouse thymocytes than did supernatant fluids from Con A-exposed BM. Interleukin-1 inhibitor activity was not detected in the supernatant fluids. These observations make it unlikely that soluble factors alone account for AM-mediated suppression. Thus, at least for the Con A-induced Ts system, AM do not mediate suppression either via better generation or greater functional expression of suppressor cells relative to BM. The paradoxically greater proliferation of lymphocytes stimulated by the supernatant fluids of Con A-exposed AM raises the possibility that suppression of Con A-stimulated lymphocyte proliferation observed when AM serve as the accessory cells in primary culture may be related to AM secretion of a molecule with IL-1-like activity.

Time-dependent enhancement of lymphocyte activation by mitogens after exposure to isolation or water scheduling

The effects of isolation and water scheduling on mitogen induced lymphocyte proliferation were investigated. Isolated rats were animals which had been raised in group-housed conditions and then transferrd to individual cages with ad lib access to water for a 1 or 2 week period. Water scheduled rats were maintained in group housing (5 rats per cage) with ad lib access to food but with access to water for a single 30 minute session each day. Responses of these groups were compared to those of animals which had been continuously group-housed with ad lib access to food and water. No differences in lymphocyte responses to phytohemagglutinin (PHA) were found 1 week after exposure to isolation. However, after 2 weeks, splenic and blood T lymphocytes from isolated animals demonstrated an increased proliferative response to sub-optimum and maximum concentrations of PHA. Splenic B lymphocyte responses to lipopolysaccharide (LPS) from isolated animals were also increased by 2- to 3-fold compared to group-housed controls. Two weeks of exposure of animals to daily water scheduling similarly increased the splenic lymphocyte proliferation. This increased responsiveness to PHA was not accompanied by a significant change in the sensitivity of the lymphocytes to PHA, in the total number of white blood cells, or the proportion of splenic T or T helper lymphocytes. Our results show that the increase in lymphocyte proliferation is time-dependent, requires greater than 1 week of exposure to isolation and is due to factors other than changes in sensitivity to mitogen or T lymphocyte number.

Effects of methimazole on human lymphocyte proliferation and natural killer cell activity

1. 1. Methimazole (MM), an antithyroid drug, was examined for its ability to modulate immune functions. The increase in [ 3H]thymidine incorporation in plant mitogen-stimulated lymphocytes and augmentation of NK cell activity by MM were used as a measure of the immunomodulatory activity of MM. 2. 2. The results demonstrated that lymphocytes from 5 different donors had a mean increase of 632% of [ 3H]thymidine incorporation in the presence of MM at a concentration of 114.2 μg/ml ( P < 0.005). 3. 3. Lymphocyte response to PHA, Con A or PWM was potentiated by 27 to 482% in the presence of MM. 4. 4. The MM mediated increase in lymphocyte proliferation was more obvious in cases where the mitogenic stimulation was low. 5. 5. Lymphocyte cytotoxicity to both K562 cells and malignant B cells was also augmented when lymphocytes were cultured in the presence of MM. 6. 6. A maximal effect was observed when lymphocytes were treated with a concentration of 20 μg/ml of MM for 12–16 hr. 7. 7. Maximum augmentation was usually exerted when the NK cell activity of cultured lymphocytes was low. 8. 8. This was particularly seen with lymphocyte from cultured B cell leukemia (3163).

Induction of immunotoxicity in mice by polyhalogenated biphenyls.

Acute administration of Aroclor-1254 (500 mg/kg) or 3,4,5,3',4',5'-hexabromobiphenyl (HBB) (2-6 mg/kg) IP, profoundly inhibited the plaque forming response to subsequent challenge with sheep erythrocytes in Ah locus positive (C57Bl/6N or B6C3F1N) mice. These studies showed: the immunotoxicity results paralleled enzyme induction results insofar as HBB was approximately 100 times more potent than Aroclor 1254; neither Aroclor nor HBB treatment caused significant induction in the Ah locus negative DBA/2N mice; when B6C3F1 mice were challenged with sheep red blood cells (SRBC) 6 or 16 weeks post Aroclor 1254 treatment, substantial recovery of a PFC response was observed; when these compounds were administered to older (76-week-old) (B6C3F1 mice, severe depression of a PFC response was observed. In contrast to its profound depression of a PFC response, Aroclor-1254 (up to 1250 mg/kg) caused slight increases in lymphocyte proliferation induced by either T or B cell mitogens. A single 500 mg/kg dose of Aroclor-1254 also suppressed the ability of recipient B6C3F1 animals to reject a challenge with either the syngenic fibrosarcoma (PYB6) or the gram negative pathogen (Listeria monocytogenes).

Augmentation of chinese hamster lymphocyte stimulation by cysteine

Addition of 2-mercaptoethanol (2-ME) in a final concentration of 40 μM to Chinese hamster lymphocyte cultures results in a remarkable increase in lymphocyte proliferation. The same marked increase in lymphocyte proliferation is obtained when cysteine in a final concentration of about 4 mM is added totthe cultures. Optimum lymphocyte proliferation after addition of 2-ME and different amounts of cysteine occurs on different days. The optimum time of culture depends on cysteine concentration. With higher amounts of cysteine longer culture times are needed for optimal stimulation.

Different optimal PHA concentrations for stimulation of Chinese hamster lymphocytes in cultures supplemented with foetal calf serum or horse serum

Chinese hamster lymphocyte cultures were supplemented with foetal calf serum (FCS) or horse serum (HS). Addition of 2-mercaptoethanol (2-ME) to cultures supplemented with these sera resulted in a marked increase in lymphocyte proliferation. The PHA concentrations necessary for optimal lymphocyte stimulation were much lower in cultures supplemented with HS than with FCS. Phytohaemagglutinin (PHA) concentrations optimal for stimulation of a given number of lymphocytes in cultures supplemented with FCS often gave strong inhibition of similar cultures supplemented with HS.

Failure of autologous oral epithelia to activate RAS lymphocytes

The capacity of epithelial cells obtained from human and mucosa to activate peripheral blood lymphocytes from normal subjects and from patients with recurrent aphthous stomatitis (RAS) has been investigated. Increases in [ 3H]thymidine incorporation were observed when normal human lymphocytes were incubated with mitomycin C-treated epithelial cells or with mitomycin C-treated lymphocytes obtained from normal, homologous donors. Autologous epithelial cells induced weaker but still detectable increases in lymphocyte proliferation. The responsiveness of RAS lymphocytes to autologous epithelial cells was unaltered when both cell populations were obtained during phases of oral ulceration or during periods of remission and was not different in magnitude from responses of normal lymphocytes to their autologous cells. These results indicate that human oral epithelia possess alloantigens and autoantigens capable of initiating cellular immune responses in vitro but apparently lack the autoantigen implicated in the pathogenesis of RAS.

T-cell mediated suppression in the MRL mouse

MRL/lpr mice possess an autosomal recessive gene, lpr, which is associated with lymphoproliferation and acceleration of autoimmune disease. Lymphoproliferation has been ascribed to a single gene defect predominantly affecting the T-lymphocyte component of the immune system. MRL/++ mice do not possess the lpr autosomal recessive mutation and do not develop early lymphadenopathy. T-lymphocyte functional activity was studied in these mice using the polyclonal T-cell mitogens PHA and Con A. Our results indicated a significant suppression of the spleen and lymph node response of MRL/lpr mice to these polyclonal mitogens as compared to the MRL/++ response noted as early as 6 weeks of age. In addition, there was a progressive decline in the MRL/lpr spleen and lymph node cell mitogenic responses with increasing age. Spleen and lymph node cells from 20-week MRL/lpr mice were also relatively unresponsive in the mixed lymphocyte culture reaction as compared to cells from MRL/ ++ or BALB/c mice. The in vitro proliferative response of the MRL mice was further examined with respect to possible accessory cell modulation by both macrophages and T cells. It was found that in 20-week MRL/lpr lymph nodes a significant degree of suppression of lymphocyte proliferation could be mediated by the MRL/lpr T cell. Increased lymphocyte proliferation to a mitogenic signal could only be demonstrated in those MRL/lpr mice 3 weeks of age.

Freezing Of Rat Lymphocytes

Spleen lymphocyte proliferation, as measured by 3H-thymidine incorporation induced by phytohaemagglutinin (PHA), was increased after freeze-thawing with 10% dimethyl sulphoxide. Depletion or intoxication of macrophages in fresh spleen cell preparations also increased lymphocyte proliferation in response to PHA. On the other hand, freezing of macrophage-depleted spleen cell suspensions lowered 3H-thymidine uptake of stimulated cultures. At concntrations above 3%, macrophages added to cultures of fresh purified lymphocytes showed a dose-dependent inhibitory effect on the PHA response, and fresh macrophages were more inhibitory than frozen-thawed macrophages. Purified lymphocytes mixed with 10% macrophages showed a higher response after freeze-thawing. It is concluded that macrophages suppress the lymphoproliferative response to PHA in rat spleen cell cultures, and that these macrophages are more sensitive than lymphocytes to the present freeze-thaw process.

Increased stimulatory capacity of spleen cells from adult thymectomized mice in mixed lymphocyte reactions.

Conflicting results have been reported concerning the effect of adult thymectomy (A-Tx) on the mixed lymphocyte reaction (MLR) response. Our purpose was to test the reverse question, namely the effect of A-Tx on the stimulatory capacity of mouse lymphocytes carrying allelic disparities at the Mls and the H-2 loci. Spleen cells from A-Tx CBA donors were found to be significantly more stimulating than cells from normal donors. That A-Tx could eliminate suppressor T cells involved in MLR regulation or in preventing back stimulation is not likely according to our data. An increment in expression or in accessibility of Mls or H-2 antigenic determinants induced by A-Tx is no more likely, since a smilar increase in lymphocyte proliferation was observed in syngeneic cultures. The most probable explanation remains that A-Tx discloses a strongly stimulatory subpopulation, perhaps acting in part nonspecifically. The hypothesis of an enrichment in B cells versus a loss of T cells is not compatible with our findings, since B-cell-enriched fractions from various origins never attained the stimulating ability disclosed by A-Tx cells. Moreover, the cell involved is theta-positive, although slightly nylon-wool-adherent, and thus shares several properties with immature T cells involved in auto-rosette formation.

Growth of B lymphocyte colonies in vitro from mouse lymphoid organs.

TECHNIQUES now exist for obtaining clonal growth in semi-solid agar of mouse neutrophil, macrophage, eosinophil, erythropoietic and megakaryocytic colonies1–5. Previous attempts to obtain colony formation by mouse lymphoid cells, however, were unsuccessful and cultured lymphocytes died very quickly, even in the presence of known lymphocyte mitogens. Mercaptoethanol and related substances have been shown to increase lymphocyte proliferation in liquid cultures6 and colony formation in agar by mouse plasmacytoma cells7. Based on these observations, attempts were made to obtain clonal growth of mouse lymphoid cells in agar medium supplemented with 2-mercaptoethanol.