Phytohemagglutinin improves the development and ultrastructure of in vitro-cultured goat (Capra hircus) preantral follicles

The objective this study was to determine the effect of phytohemagglutinin (PHA) on survival, growth and gene expression in caprine secondary follicles cultured in vitro. Secondary follicles (∼0.2 mm) were isolated from the cortex of caprine ovaries and cultured individually for 6 days in α-MEM+ supplemented with PHA (0, 1, 10, 50, 100, or 200 µg/mL). After 6 days of culture, follicle diameter and survival, antrum formation, ultrastructure and expression of mRNA for FSH receptors (FSH-R), proliferating cell nuclear antigen (PCNA), and neuronal nitric oxide synthase were determined. All treatments maintained follicular survival [α-MEM+ (94.59%); 1 µg/mL PHA (96.43%); 10 µg/mL PHA (84.85%); 50 µg/mL PHA (85.29%); 100 µg/mL PHA (88.57%), and 200 µg/mL PHA (87.50)], but the presence of 10 µg/mL PHA in the culture medium increased the antrum formation rate (21.21%) when compared with control (5.41%, P < 0.05) and ensured the maintenance of oocyte and granulosa cell ultrastructures after 6 days of culture. The expression of mRNA for FSH-R (2.7 ± 0.1) and PCNA (4.4 ± 0.2) was also significantly increased in follicles cultured with 10 µg/mL PHA in relation to those cultured in α-MEM+ (1.0 ± 0.1). In conclusion, supplementation of culture medium with 10 µg/mL PHA maintains the follicular viability and ultrastructure, and promotes the formation of antral cavity after 6 days of culture in vitro.

Interferon-gamma and interleukin-10 production by mononuclear cells from patients with advanced head and neck cancer

OBJECTIVE: This study aims to evaluate the production of interferon-gamma and interleukin-10 by stimulated peripheral blood mononuclear cells isolated from patients with supraglottic laryngeal cancer before and after surgical treatment. METHODS: Fourteen patients with advanced supraglottic laryngeal cancer were studied. Cultures of peripheral blood mononuclear cells isolated during the preoperative and late postoperative periods were stimulated with concanavalin A and Bacille Calmette-Guerin, and the supernatant concentrations of interferon-gamma and interleukin-10 were measured. RESULTS: For non-stimulated cultures, the interferon-gamma levels produced by the preoperative period and the late postoperative period cultures were lower than the levels produced by the control group cultures. The interferon-gamma levels after stimulation with concanavalin A were higher in the late postoperative period cultures than in the preoperative evaluation cultures. Stimulation with Bacille Calmette-Guerin led to the production of similar levels of interferon-gamma and interleukin-10 by all cultures; thus, stimulation increased the levels of interferon-gamma produced by both the preoperative and postoperative cultures relative to the levels produced by the corresponding unstimulated cultures. CONCLUSION: Patients with advanced supraglottic laryngeal cancer exhibit an in vitro deficiency in interferongamma secretion by mononuclear cells. Stimulated cells seem to recover this function during the postoperative period.

Aging reduces the primary humoral response and the in vitro cytokine production in mice

Aging is accompanied by a decrease in several physiological functions that make older individuals less responsive to environmental challenges. In the present study, we analyzed the immune response of female BALB/c mice (N = 6) of different ages (from 2 to 96 weeks) and identified significant age-related alterations. Immunization with hapten-protein (trinitrophenyl-bovine serum albumin) conjugates resulted in lower antibody levels in the primary and secondary responses of old mice (72 weeks old). Moreover, young mice (2, 16, and 32 weeks old) maintained specific antibodies in their sera for longer periods after primary immunization than did old mice. However, a secondary challenge efficiently induced memory in old mice, as shown by the increased antibody levels in their sera. The number of CD4+ and CD8+ T cells in the spleen increased until 8 weeks of age but there was no change in the CD4+/CD8+ ratio with aging. Splenic T cells from old mice that had or had not been immunized were less responsive to concanavalin-A and showed reduced cytokine production compared to young mice (IL-2: 57-127 vs 367-1104 pg/mL, IFN-g: 2344-12,836 vs 752-23,106 pg/mL and IL-10: 393-2172 vs 105-2869 pg/mL in old and young mice, respectively). These data suggest that there are significant changes in the organization of the immune system throughout life. However, the relevance of these alterations for the functioning of the immune system is unknown.

Artesunate and a major metabolite, dihydroartemisinin, diminish mitogen-induced lymphocyte proliferation and activation.

Artemisinin derivatives are potent antimalarial compounds that may have immunomodulatory properties. Artesunate (range 0.01-2 mirog/ml) or dihydroartemisinin (range 0.01-8 microg/ml; DHART) were added to peripheral blood mononuclear cells (PBMC) or whole blood (WB) cultures before or simultaneously upon stimulation with phytohemagglutinin (PHA), a T cell mitogen. Lymphoproliferation was then measured by 3[H]-thymidine incorporation, and CD4+ and CD8+ T cell activation was assessed by expression of CD69 or CD25 using flow cytometry. Reverse transcriptase polymerase chain reaction depicted PBMC mRNA production for interleukins 2, 4, 12, and 15, interferon-gamma, and tumor necrosis factor-alpha. Artesunate concentrations between 0.1-1.5 microg/ml reduced lymphoproliferation in PHA-stimulated PBMC and WB cultures in a generally dose-dependent manner; inhibition by DHART was similar. Removing artesunate from PBMC before PHA was added abolished the reduction. PBMCs cultured with artesunate or DHART simultaneously with PHA showed modestly reduced proportions of CD4+ and CD8+ T cells expressing CD69 and CD25. Artesunate had little effect on qualitative cytokine mRNA levels in PHA-stimulated PBMC cultures. Artesunate and DHART may diminish some PBMC responses to immunologic stimuli. Further work is warranted to define the mechanisms involved, and whether this affects malaria treatment.

Efecto de gangliosidos in vitro sobre linfocitos de pacientes chagasicos estimulados con mitogenos o con antigenos de corazón o cerebro / Gangliosides in vitro effects on lymphocytes from patients with chronic Chagas disease stimulated with mitogens or heart or brain antigens

Se estudió in vitro el efecto de gangliósidos sobre las respuestas de linfocitos de pacientes chagásicos estimulados con mitógenos o con antígenos de corazón y cerebro. La razón para efectuar este estudio fueron las evidencias que indican un rol de los linfocitos T en la producción de daños de la cardiopatía chagásica, y datos que indican que los gangliósidos pueden tener actividad sobre esas células. Además, en trabajos previos, hallamos que los linfocitos de chagásicos responden con transformación blástica (TB). Material y Métodos: se efectuaron cultivos de leucocitos de 14 pacientes chagásicos. A los cuales se adicionaron gangliósidos y en esas condiciones, se estimularon con mitógenos, o bien con antígenos de corazón humano o cerebro murino, respectivamente. Resultados: se observó inhibición parcial de la transformación blástica Inducida por mitógenos, y también hubo Inhibición parcial de la TB inducible por los antígenos de corazón o de cerebro en los linfocitos de chagásicos, siendo significativas las diferencias con respecto a los controles (p< 0.001). Conclusiones: se considera de Interés ese efecto inhibidor de gangliósidos sobre las actividades de los linfocitos de chagásicos estudiadas en estos experimentos, por ser directamente vinculables a factores de patogenia chagásica, que podrían ser Inmunomodulados.

In human Chagas'disease previous work has shown the occurrence of a T-lymphocyte CD4-positive population (a high producer of PAS-positive glycoproteins) with evidence suggesting a role in the formation of damages to the myocardium and neural structures in chagasic heart disease (ChHD). Other workers have taken such facts into consideration and have employed gangliosides (biological substances with neurotrophic and immunomodulatory properties) in chagasics with chronic cardiomyopathy and disautonomic signs, obtaining an Improvement in functional signs and a decrease in the number of PAS+ lymphocytes. In the present work we have studied the effect of mixed gangliosides (Cronassial on cell cultures of total leukocytes, or on mononuclear cells prepared through Ficoll-Hypaque. Blood was obtained from 14 patients with ChHD. Experiments were undertaken to assess the effect of policlonal mitogens Phytohaemagglutinin (Phy) and Concanavalin A (Con A) on blastic transformation, estimated by cell size and cytologic study. In addition, the production of PAS+ substances by the lymphocytes and blast were assessed. Gangliosides were added at final concentrations of 100 mg/ml or 200 mg/ ml. Cell viability was assessed by means of the Trypan blue test. With respect to blastic transformation, results showed a significant decrease in the cultures that received gangliosides 24 hours before mltogen administration, as compared with controls (p<0.001) (both for Phy and Con A). On the other hand, the production of lymphocytic PAS+ substances decreased in the cultures of chagasics in which gangliosides were added. Some of these results confirmed previous findings on the matter. The facts suggest that gangliosides can modulate some lymphocytic activities in chagasics.

Donor Specific Response of Estrogen and Progesterone on Cultured Human Melanocytes

The mechanisms of estrogen and progesterone in human cutaneous pigmentation are largely unknown. The molecular identification of estrogen receptor (ER) and progesterone receptor (PR) in the human melanocytes is of great importance to understand the mechanisms. We performed immunocytochemistry analysis and demonstrated that ER and PR were expressed in the cytoplasms and nuclei of human melanocytes. Reverse transcriptase-polymerase chain reaction (RT-PCR) and sequence analysis confirmed the expression of ER and PR at the transcriptional level. Despite of the presence of ER and PR, the physiological and pregnant levels of estrogen and progesterone showed inconsistent effects on the proliferation and tyrosinase activity of cultured human melanocytes. These results suggest that human melanocytes express ER and PR, which have a donor-specific action in human pigmentation. Further studies are needed to elucidate the induction mechanism and functions of these receptors, and the role of estrogen and progesterone in melanocytes.

Phosphorylation of glycogen synthase kinase-3beta at serine-9 by phospholipase Cgamma1 through protein kinase C in rat 3Y1 fibroblasts

Phospholipase Cgamma1 (PLCgamma1) plays an important role in controlling cellular proliferation and differentiation. PLCgamma1 is overexpressed in some tumors, and its overexpression induces solid tumors in nude mice. However, the regulatory mechanisms underlying PLCgamma1-induced cell proliferation are not fully understood. Here we show that overexpression of PLCgamma1 highly phosphorylated glycogen synthase kinase-3beta (GSK-3beta) at serine-9 in 3Y1 fibroblasts. Inhibition of protein kinase C (PKC)s with GF109203X abrogated GSK-3beta phosphorylation by PLCgamma1. We also found that steady-state level of cyclin D1 protein, but not cyclin D1 mRNA, was highly elevated in response to serum stimulation in PLCgamma1-transfected cells as compared with vector-transfected cells. Since GSK-3beta is involved in cyclin D1 proteolysis in response to mitogenic stimulation, PLCgamma1-mediated GSK-3beta phosphorylation may function as a regulation of cyclin D1 accumulation in PLCgamma1-overexpressing cells.

Selenium supplementation protects from high fat diet-induced atherogenesis in rats: role of mitogen stimulated lymphocytes and macrophage NO production.

The present study was designed to demonstrate the involvement of immune response in experimental atherogenesis. The mitogenic stimulation of lymphocytes and NO production by macrophages in experimental atherogenesis were studied. Further, influence of selenium a potent antioxidant was also studied in the disease process. Three different treatment groups of rats undertaken for study were: group 1, control; group II, high fat diet (HFD) fed group and group III, HFD+Se supplemented group. Atherogenic conditions induced have already been explained earlier [Kang BPS et al. Gen Physiol Biophys, 17 (1998) 71]. Significant increase in 3H-thymidine incorporation was obtained in lymphocytes from HFD fed animals in both presence and absence of mitogen (Con-A). However, these values decreased in group III animals, which were supplemented with selenium. Similarly, NO levels with LPS+ and LPS- macrophages also found to be higher in HFD fed group and decreased in group III. These studies reveal the protective role of selenium in HFD-induced atherogenic process.

Effect of short-term ethanol on the proliferative response of Swiss 3T3 cells to mitogenic growth factors

Both adaptive and deleterious responses of cells to ethanol are likely triggered by short-term interactions of the cells with ethanol. Many studies have demonstrated the direct effect of ethanol on growth factor-stimulated cell proliferation. Using Swiss 3T3 cells whose growth was inhibited by ethanol in a concentration-dependent manner, we further investigated the molecular mechanisms of acute ethanol treatment by examining its effect on EGF- and PDGF-mediated cellular signaling systems for the mitogenic function. Tyrosine autophosphorylation of the growth factor receptors was partially prevented by ethanol in intact cells. When ethanol was included before or after EGF stimulation, no effect on the receptor signaling was observed. Here we also report that ethanol inhibits activation of ERK induced by both EGF and PDGF. EGF-induced JNK activation was reduced but PDGF-induced rapid JNK activation was delayed by the addition of ethanol. The balance between its inhibitory and stimulatory effect on the signaling molecules might determine the rate of cell growth.

Mitogenic activity of fetal bovine serum, fish fry extract, insulin-like growth factor-I, and fibroblast growth factor on brown bullhead catfish cells--BB line

Bioassays were performed to assess the effects of different levels of growth medium supplementation with fetal bovine serum (FBS), fish fry extract (FE), combinations of FBS and FE, and addition of insulin-like growth factor I (IGF-I) and fibroblast growth factor (FGF) on the proliferation of brown bullhead catfish cells (BB line). Treatments (n = 4) were: 2.5, 5, 10, and 15.0 FBS or FE and 5/2.5, 5/5, 10/2.5, and 10/5 of a FBS/FE combination as supplement to the growth medium, or the addition of 0.1, 1, 2.5, 10, 25, and 75 ng/ml of either IGF-I or FGF to the growth media. Initial cell density was 1.1 x 10(6) cells per well on uncoated 24-well plates. Incubation temperature was 29.5 +/- 0.7 degrees C. Six hours after plating, initial culture medium was removed, plates rinsed with Dulbecco's phosphate buffered saline, treatment media added, and cells allowed to proliferate for 24 hours. Another bioassay was performed with rat myoblast omega cells (RMo) using the same levels of growth medium supplemented with FBS, FE and FBS/FE. Base growth medium was Dulbecco's MEM. The initial cell density was 7.2 x 10(6) cells per well, and the bioassay was carried out at 36.0 +/- 0.5 degrees C, on a 95 air, 5 CO2 incubator. Increasing levels of FBS had a positive effect (P < 0.05) on the proliferation of both BB and RMo cells. Increasing levels of FE had a negative effect (P < 0.05) on the proliferation of BB cells and totally inhibited the proliferation of RMo cells at any level of supplementation. Higher levels of FE on the FBS/FE combinations presented a negative effect on the proliferation of both BB and RMo cells (P < 0.05). Insulin-like growth factor I had a positive quadratic effect (P < 0.05) on the proliferation of BB cells. Apparently, mammalian growth factors slightly stimulated mitogenic activity in fish cells, while FE contained factors which inhibited the mitogenic activity of RMo and BB cell lines.

Detection of a factor released by L5178Y lymphoblasts that inhibits mouse Macrophage-Activation induced by lipopolysaccharides

Background. Several factors inhibit cellular immune response by deactivating macrophages, but very few, such as those described here, prevent macrophage activation. Methods. Ascites liquid from 12-day-old BALB/c mice bearing 5178Y lymphoma tumors was collected, and cell-free ascites liquid (CFAL) was separated from lymphoblasts. The supernatant (SI) was obtained from the homogenized and centrifuged lymphoblasts Then, macrophage cultures contaning 0.2 X 10 a the sixth cells from lymphoma-bearing or hearthly mice were added to 10 µL of CFAL or S1, plus 5 µg of lipopolysaccharides (LPS)/mL, 40 U interferon-ç or a blend of both. Macrophages were incubated with CFAL or S1 prior to or after adding the activators to investigate whether any of the previously mentioned lymphoma fraction inhibited macrophage activation or whether they deactivated them. The effect of CFAL or S1 was estimated as the diminution of the amount of nitric ixide released by the experimental macrophage cultures with respect to controls (activated macrophages treated with none of the lymphoma fractions). Results. LPS, IFN-ç, and the LPS/ç blend activated macrophages from both lymphomabearing and healthy mice. None of the lymphoma fractions deactivated macrophages. CFAL, but not S1, inhibited the macrophage activation, i.e., the percentage of inhibition of nitric oxide releasing 76.7 percent in macrophages from healthy and lymphomabearing mice, respectively. In addition, CFAL was unable to inhibit macrophage-activation effect of IFN-ç or the LPS/IFN-ç blend. Conclusions. Mouse L5178Y Lymphoma releases a factor that in vitro inhibits the macrophage activation induced by LPS, but not by IFN-ç controls

Chronic hepatitis B virus carriers have low lymphoproliferative responses to HBsAg and reduced interleukin-2 synthesis.

BACKGROUND: Chronic carriers of hepatitis B virus (HBV) have impairment of lymphoproliferative responses. Recently HBV infection of peripheral blood mononuclear cells (PBMC) has been reported. The defect in the proliferative capacity of carrier PBMC has not been correlated to the presence of HBV in these cells. METHODS: PBMC of fourteen HBV carriers and 14 healthy individuals were stimulated with phytohemagglutinin (PHA), pokeweed mitogen (PWM) or anti-CD3 for 3 days and with HBsAg and purified protein derivative (PPD) for 6 days. The supernatants of unstimulated and PHA-stimulated PBMC cultures were bioassayed for interleukin-2 (IL-2); the supernatants of unstimulated and lipopolysaccharide (LPS)-stimulated cultures were bioassayed for IL-1. DNA extracted from PBMC was hybridized with a 32P-labeled HBV probe to look for HBV DNA. RESULTS: HBV carriers' PBMC showed impaired responses to PHA, PWM and anti-CD3. No carrier demonstrated lymphoproliferative response to hepatitis B surface antigen (HBsAg). Seven of eight carriers with impaired HBsAg-specific proliferative responses who were tested for their response to an unrelated antigen showed a positive response to PPD. PBMC from HBV carriers produced similar amounts of IL-1 as normal PBMC on LPS stimulation; however, they produced significantly lower amounts of IL-2 as compared to normal PBMC under both spontaneous and PHA-stimulated conditions. HBV DNA was demonstrable in the PBMC of all fourteen carriers. CONCLUSIONS: The abnormal immune function found in chronic HBV carriers may be a consequence of replicative viral infection of the mononuclear cells.

Effect of gamma irradiation on chemical and biological properties of lipopolysaccharide from Salmonella typhimurium.

Lipopolysaccharide (LPS) from S. typhimurium on exposure to gamma-radiation resulted in decrease in toxicity and was less mitogenic, Silver stained profiles of irradiated LPS on polyacrylamide gels revealed complete loss of its heteropolysaccharides which was confirmed further by analysing lipid A and LPS from Salmonella minnesota Re mutants on SDS-PAGE. Glucosamine and 2-keto 3-deoxy-octonate(Kdo) contents were significantly decreased on treatment. Lipid A obtained by removal of heteropolysaccharides from LPS was less toxic on exposure to gamma radiations.

Changes in the expression of c-myc, RB and tyrosine-phosphorylated proteins during proliferation of NIH 3T3 cells induced by hyaluronic acid

We have shown that hyaluronic acid stimulates the proliferation of quiescent NIH 3T3 cells. We have shown that treatment of 1 mg/ml hyaluronic acid results in increase of tyrosine phosphorylation of two proteins, MW 124 kDa and 60 kDa as detected by anti-tyrosine antibodies by Western blot analysis. Maximum phosphorylation occurred within 2 h after addition of 1 mg/ml hyaluronic acid. Stimulation of proliferation was also accompanied by increase in c-Myc protein, which was inhibited by amlloride, an inhibitor of Na+/H+ antiporter and EGTA and increase in the steady state level of pRb, the RB gene product. These results suggest that the intracellular signal transduction pathways that mediate the stimulatory effects of hyaluronic acid on cellular proliferation are similar to those of growth factors.

Suppressor activity in Leishmania donovani-infected hamster serum: reversion by delipidated bovine serum albumin and role in cell cycle events

Visceral leishmaniasis caused by Leishmania donovani, is a chroníc disease with a high mortality rate. This protozoan induces a serious dysfunction of the immune system characterized by suppression of the cellular response to parasite antigens. We provide evidence for the involvement of lipids in the immunological alterations of experimental leishmaniasis. Sera obtained from 60-day-infected hamsters present increased triglyceride levels. Inhibition of cell proliferation was observed when splenocytes from normal hamsters were stimulated with concanavalin A in the presence of 3 per cent infected hamster serum (IHS) (Control 50 + 3 (x 10(3)) Cpm; IHS 5 ñ 1 (X 10(3)) cpm). This inhibition was reversed by the addition of 5 mg/ml of delipidated bovine serum albumin (BSA) to the cultures (Control 65 ñ 1 (X 10(3)) cpm; IHS 75 ñ 3 (x 10(3)) cpm). The inhibitory effect of IHS was demonstrable only when added to the culture simultaneously with the mitogen. This effect was not as intense on fresh, pre-activated cells or on the CTLL-2 cells. This cell line stimulated by IL-2 in the presence of IHS is only marginally inhibited (about 20 per cent inhibition). The suppressor effect on CTLL-2 was not reversed by the addition of increasing doses of IL-2 (up to 100 U/ml) to cultures. The inhibition of the proliferative response of the CTLL-2 cells caused by IHS was also reversed by the addition of delipidated BSA. Our data suggest a role for fatty acids in the infected hamster serum-induced suppression of normal or L. donovani-infected cell proliferation.

Action of plasma and liver extract from adult mice on the mitotic activity of young mouse liver

Se utilizaron ratones C3HS, endocriados, standardizados para análisis de periodicidad. Ciento setenta ratones de 25 ñ 2 días de edad fueron unyectados a las 16:00 horas con solución fisiológica, plasma o extracto de hígado de 27 machos de 90 días de edad. Los controles fueron realizados a las 08/16, 12/20, 16/24, 08/40, 12/44, 16/28, 08/64, 12/68 y 16/72 (hora día/hora post-inyección) y fue determinada la actividad mitótica de los hepatocitos y células litorales. La inyección de pequeñas dosis de extracto y plasma inhibe la actividad mitótica de los hepatocitos durante los dos primeros días de control. En el tercer día aparece una onda compensatoria. El extracto inhibe la actividad mitótica de las células litorales solo el primer día de control, mientras que el plasma inhibe esta variable el segundo y tercer día

Maternal fetal immunological relationship particularly mycobacterial immunity.

Thirty-nine paired maternal and cord blood from normal full term deliveries were tested for lymphocyte function by proliferative response to mitogens-Phytohemagglutinin-P (PHA) and Poke week mitogens (PWM). Monocyte function was assessed by the ability of the monocytes to release hydrogen peroxide (H2O2) in response to standard stimulus (PMA). Mycobacterial immunity was assessed by lymphocyte proliferative response to purified proteins derivative (PPD) and IgM and IgG antibody response to H37Rv and 5 atypical mycobacteria. Lymphocyte functions were significantly lower in cord blood (PHA 20.6, PWM 21.2) as compared with maternal blood (PHA 65.8, PWM 37.8). The capacity of fetal monocytes to release H2O2 was comparable to maternal monocytes. The mean proliferative response of fetal lymphocytes to tubercular protein (PPD) was 0.67 as compared (P less than 0.01) to maternal lymphocytes (3.79). Nearly 86% of the cord blood did not show any response to PPD. None of the cord blood showed IgM antibody response to H37Rv nor to any of the range of 5 atypical mycobacteria though maternal IgM and IgG response was present. There was only passive transfer of IgG antibody from mother to fetus. Hence, though this is a highly endemic area for atypical mycobacteria and M. tuberculosis, there was apparently no transplacental transfer of antigen in normal sensitized mothers.

Bovine interleukin 2: production kinetics in normal and in vivo antigen-primed cattle.

Conditions influencing production kinetics of bovine interleukin 2 (IL-2), viz. cell concentration, mitogen and its concentration, length of incubation, nutrient medium and in vivo antigen-priming were investigated. Peripheral blood mononuclear cells (PBL) of outbred cattle of different age groups showed considerable variation in their ability to secrete IL-2 which possibly reflects their immune competence. Of the cultures initiated with PBL, 5 x 10(6) cells/ml cultured in serum free Iscove's medium and stimulated with 5 micrograms Con A/ml for 24 hr produced maximal amount of IL-2 activity. In vivo antigen-priming of bovine lymphocytes with the live attenuated rinderpest virus revealed that IL-2 production was not affected by rinderpest virus but the in vivo antigen-priming possibly resulted in concomitant production of suppressor factor(s) which suppressed the already produced IL-2. The implications of this factor(s) in relation to regulation of immune responses in the disease process are discussed.

Immunomodulatory role of thyroid hormones: in vitro effect of tetraiodothyronine (T4) on mitogen induced blastogenic response of lymphocytes.

An attempt was made to find out the immunomodulatory role of thyroid hormone, tetraiodothyronine (T4), and its effect on in vitro mitogen induced blastogenesis. Human peripheral blood lymphocytes (PBL) were subjected to phytohaemagglutinin (PHA) concanavalin-A (Con. A) and pokeweed mitogen (PWM) in presence or absence of T4. Basal blastogenic response was significantly enhanced in dose related manner by T4. PHA and Con.A induced response was depressed significantly (r = -0.975 and r = -0.945) whereas less than 50 ng T4 in presence of PHA showed mild stimulation. On the other hand, PWM induced response in presence of T4 was enhanced significantly in dose related manner.

Mitogen induced LIF-production in T-lymphocyte subpopulations

El método de rosetas con eritrocitos de pollo recubiertos de IgG se ha utilizado junto con separación por flotación en ficoll-hypaque para obtener subpoblaciones de células enriquecidas o disminuidas de linfocitos T con receptor para Fc de IgG (Tg). Estas poblaciones celulars se han utilizado para determinar producción de LIF a diferentes concentraciones de los mitógenos, utilizando un método en microgota de agarosa. De esta manera, hemos podido observar una respuesta semejante en las diferentes poblaciones celulares hacia concanavalina A y una respuesta diferencial hacia fitohemaglitinina donde por lo general se observa una respuesta negativa de la población enriquecida con células Tg mientras que las poblaciones de linfocitos totales o aquellas en las que se han eliminado las Tg dan una respuesta positiva al segundo mitógeno