Effects of sex steroids on immunoglobulin M production by Epstein-Barr virus-transformed B-cell line SKW6-CL4

Sex Differences in Older Adults' Immune Responses to Seasonal Influenza Vaccination

Background: Sex differences in immune responses to influenza vaccine may impact efficacy across populations. Methods: In a cohort of 138 older adults (50-74 years old), we measured influenza A/H1N1 antibody titers, B-cell ELISPOT response, PBMC transcriptomics, and PBMC cell compositions at 0, 3, and 28 days post-immunization with the 2010/11 seasonal inactivated influenza vaccine. Results: We identified higher B-cell ELISPOT responses in females than males. Potential mechanisms for sex effects were identified in four gene clusters related to T, NK, and B cells. Mediation analysis indicated that sex-dependent expression in T and NK cell genes can be partially attributed to higher CD4+ T cell and lower NK cell fractions in females. We identified strong sex effects in 135 B cell genes whose expression correlates with ELISPOT measures, and found that cell subset differences did not explain the effect of sex on these genes' expression. Post-vaccination expression of these genes, however, mediated 41% of the sex effect on ELISPOT responses. Conclusions: These results improve our understanding of sexual dimorphism in immunity and influenza vaccine response.

Danazol induces prolonged survival of fully allogeneic cardiac grafts and maintains the generation of regulatory CD4(+) cells in mice

Danazol, a derivative of testosterone, is useful for treatment of endometriosis as well as pretreatment for in vitro fertilization and embryo transfer, although its mechanisms of action are unclear. The aim of this study was to investigate the effect of danazol on alloimmune responses in murine heart transplantation. CBA male mice (H2(k) ) underwent transplantation of C57BL/6 male (H2(b) ) hearts and received a single dose of danazol (0.4, 1.2 or 4mg/kg/day) by intraperitoneal injection on the day of transplantation and for 6days thereafter. An adoptive transfer study was performed to determine whether regulatory cells were generated. The median survival time (MST) of allografts in danazol-treated (1.2 and 4mg/kg/day) mice was 28 and 63days, respectively, compared with 7days in untreated mice. Moreover, secondary CBA recipients given whole splenocytes or CD4(+) cells from primary danazol-treated (4mg/kg/day) CBA recipients 30days after transplantation had prolonged allograft survival (MSTs, 29 and 60days, respectively). Cell proliferation, interleukin (IL)-2 and interferon-γ were suppressed in danazol-treated mice, whereas IL-4 and IL-10 were up-regulated. Moreover, danazol directly suppressed allo-proliferation in a mixed leukocyte culture. Flow cytometry showed an increased CD4(+) CD25(+) Foxp3(+) cell population in splenocytes from danazol-treated mice. Danazol prolongs cardiac allograft survival and generates regulatory CD4(+) cells.

Androgens and estrogens modulate the immune and inflammatory responses in rheumatoid arthritis

Generally, androgens exert suppressive effects on both humoral and cellular immune responses and seem to represent natural anti-inflammatory hormones; in contrast, estrogens exert immunoenhancing activities, at least on humoral immune response. Low levels of gonadal androgens (testosterone/dihydrotestosterone) and adrenal androgens (dehydroepiandrosterone and its sulfate), as well as lower androgen/estrogen ratios, have been detected in body fluids (that is, blood, synovial fluid, smears, salivary) of both male and female rheumatoid arthritis patients, supporting the possibility of a pathogenic role for the decreased levels of the immune-suppressive androgens. Several physiological, pathological, and therapeutic conditions may change the sex hormone milieu and/or peripheral conversion, including the menstrual cycle, pregnancy, the postpartum period, menopause, chronic stress, and inflammatory cytokines, as well as use of corticosteroids, oral contraceptives, and steroid hormonal replacements, inducing altered androgen/estrogen ratios and related effects. Therefore, sex hormone balance is still a crucial factor in the regulation of immune and inflammatory responses, and the therapeutical modulation of this balance should represent part of advanced biological treatments for rheumatoid arthritis and other autoimmune rheumatic diseases.

B cell subsets in postmenopausal women and the effect of hormone replacement therapy

OBJECTIVES

In elderly subjects the capacity for antibody production is depressed. This immunosenescence state of humoral immunity is associated with the occurrence of autoimmune disorders involving CD5+ B (B-1) cells. Since estrogen is capable of stimulating the production of autoantibodies, this sex steroid hormone may be a contributing cause of the higher incidence of autoimmune diseases in women. In the present study, B cell subsets in women during the postmenopausal period was determined. The effect of hormone replacement therapy (HRT) on B cell subsets was examined to establish whether the administration of gonadal hormones influence humoral immunity in postmenopausal women.

METHODS

Forty six untreated pre- and postmenopausal women and 39 women on HRT were studied. The proportion of B-1 (CD5+) and conventional CD5- B (B-2) lymphocytes was determined by two-color flow cytometry. Serum autoantibodies to a nuclear antigen and to interleukin (IL)-1alpha were measured by immunofluorescence and by radioimmunoassay, respectively. Thirteen women were examined prospectively before and during HRT.

RESULTS

In late postmenopausal women (> or = 30 years postmenopausal period), the proportion of B-2 cells was significantly reduced (p<0.01) compared to those of premenopausal and perimenopausal women. HRT induced a significant (p<0.01) increase in the percentage of B-2 cells, while that of B-1 cells remained unchanged. HRT did not affect autoantibody production.

CONCLUSION

HRT may retard the progress of immunosenescence by increasing the production of B-2 cells. Moreover, HRT appears not to increase the risk of autoimmune diseases developing in postmenopausal women.

Different roles for androgens and estrogens in the susceptibility to autoimmune rheumatic diseases

It is now documented that androgens and estrogens modulate susceptibility and progression to autoimmune rheumatic diseases. At any concentration, androgens seem to be primarily suppressive on cellular and humoral immunity, whereas at physiologic concentrations, estrogens seem to enhance humoral immunity. Further research should focus on the different and frequently opposite effects exerted by physiologic and pharmacologic doses of estrogens (dose-related effects). In addition to the influence of endogenous estrogen fluctuations (i.e., during pregnancy, postpartum, menstrual periods, menopause), estrogen replacement therapy, and the use of oral contraceptives, the susceptibility to autoimmunity might be increased by the environmental estrogens (xenobiotics). Further studies must be directed to the inflammatory mediators (i.e., cytokines) that seem to alter the peripheral metabolism of sex hormones and complicate the effects of sex hormones on susceptibility to autoimmunity. Finally, genetic factors might further interfere with the roles of androgens and estrogens in selected individuals.

Estrogen enhances immunoglobulin production by human PBMCs

BACKGROUND

It has been suggested that estrogen may enhance humoral immune responses and may be involved in the pathogenesis of autoimmune diseases.

OBJECTIVE

We studied the in vitro effects of 17beta-estradiol (E2 ) on spontaneous immunoglobulin production by human PBMCs.

METHODS

PBMCs from healthy human volunteers were cultured with E2. Levels of IgG and IgM and cytokine activity were measured by ELISA. Proliferation was determined by [3H]-thymidine uptake. The cell viability was assessed by a trypan blue exclusion test.

RESULTS

E2 enhanced IgG and IgM production of PBMCs both from men and women without altering cell viability and proliferation. The stimulatory effect of E2 was revealed at 10(-10) mol/L, increased in a dose-dependent fashion, and was maximized at 10(-8) mol/L. IgG production of PBMCs in the presence of E2 (10(-8) mol/L) was 220% of control cells, and that of IgM was 211%. Immunoglobulin production of E2 -treated B cells was slightly higher than that of control cells; IgG production was 161% of control cells, and that of IgM was 157%. Anti-IL-10 antibody partially blocked the E2 effect on immunoglobulin production of PBMCs; anti-IL-10 reduced IgG production in the presence of E2 from 206% to 154% of control cells, and that of IgM from 206% to 152%. E2 increased IL-10 production of monocytes up to 250% of control level, but it did not affect that of T cells or B cells. Exogenous IL-10 (1 U/mL) further enhanced E2 -induced increase of immunoglobulin production by B cells, although this level of IL-10 alone was ineffective for B cells.

CONCLUSION

These results suggest that E2 may increase immunoglobulin production of human PBMCs mainly by increasing IL-10 production of monocytes. The results also support that E2 may act as an important stimulator for human humoral immunity.

Influence of ovarian hormones on urogenital infection

Numerous studies have examined the influence of hormones on infectious diseases and there is now a wealth of data relating to the more specific effect of the sex hormones, oestrogen and progesterone, on urogenital infections. The interaction between these hormones and the immune system is complex and the variation of hormonal effect between species further complicates the true picture as related to humans. Although it is difficult therefore to draw general conclusions regarding predominant effects of specific hormones, there is the suggestion that oestrogen enhances the pathogenicity of many urogenital micro-organisms. Our understanding of the influential role played by sex hormones in disease pathogenesis is at an early stage and illustrates well the importance of drawing together and interpreting as a whole both epidemiological and molecular studies.