Maternal blood B-cell (CD19+) percentages and serum immunoglobulin concentrations correlate with breast-feeding behavior and serum prolactin concentration

PROBLEM

Lactating women recover from pregnancy-induced immunosuppression while actively secreting immunologically active agents into milk. Few clinical studies have examined changes in postpartum maternal immune status or explored mechanisms.

METHOD OF STUDY

We measured blood B-cell (CD19+) percentages and serum concentrations of immunoglobulin (Ig) G, IgM, and IgA at 1 to 2 weeks, 1 month, and 2 months postpartum in a longitudinal study of seven healthy, lactating women.

RESULTS

More frequent or extended breast-feeding sessions were correlated with lower CD19+ percentages, reduced serum IgG, and higher serum IgA and IgM concentrations. CD19+ percentages were correlated negatively with serum prolactin concentrations. Blood samples drawn before and 30 min after breast-feeding did not differ in CD19+ percentages or serum Ig concentrations.

CONCLUSIONS

These findings confirm our previous cross-sectional study showing a negative correlation between CD19+ percentages and serum prolactin. Because lactation practices are modifiable, these findings suggest that women can influence the course of lactation-associated immunologic changes.

Postpartum maternal blood helper T (CD3+CD4+) and cytotoxic T (CD3+CD8+) cells: correlations with iron status, parity, supplement use, and lactation status

Iron deficiency reduces T cell counts; however, iron sufficiency is difficult to maintain during pregnancy and to reestablish in the early postpartum period. This cross-sectional study examined relations among postpartum maternal iron status, parity, lactation, supplement use, and maternal blood T cell populations. Sixty lactating and 41 nonlactating postpartum (NLPP) women at 1-2 wk and 1, 2, 4, or 8 mo postpartum and 13 nulliparous women were studied. Among multiparous women, multiple linear regression showed that relative percentages and absolute numbers of CD3+CD8+ cells were correlated positively with maternal serum transferrin saturation. In a separate multiple linear regression model, multiparous NLPP women who did not use multivitamin and mineral supplements had lower CD3+CD4+ cell percentages in the first month postpartum than did nulliparous control women. Lactating women who used supplements, however, had reduced CD3+CD4+ percentages 4-8 mo postpartum compared with control women. CD3+CD4+ percentages did not differ among control women, NLPP women who used supplements, or lactating women who did not use them. These results suggest that nutritional factors such as maternal iron status and use of dietary supplements play a role in a mother's postpartum immune status.

Relationship between serum prolactin, lactation and changes in maternal blood B-cell (CD19+) percents during the first 8 months post-partum

Lactation is an immunologically unique state when immune factors are produced by the mother for the protection of the infant rather than the mother. While several studies have focused on the immunological composition of human milk, much less information is available on maternal immune status during lactation. Sixty-four lactating and 43 bottle-feeding women at 1-2 weeks, 1, 2, 4 or 8 months post-partum were studied in a cross-sectional design, with 14 nulliparous women as controls. Flow cytometry analysis of peripheral blood lymphocytes showed dynamic, post-partum changes in the B-cell subpopulation. Among lactating women, the relative percents of CD19+ B-cells were significantly lower (P < 0.05) than control levels at 1-2 weeks and 1 month post-partum, but showed a significant, polynomial-linear rise (P < 0.05) over time, reaching control values by 2-4 months post-partum. Bottle-feeding women had an earlier rise in the percentage of CD19+ cells, with relative percents always significantly higher than their lactating counterparts. The differing patterns may be due to changes in serum prolactin concentrations because, among the post-partum women, relative percents of CD19+ cells were negatively correlated with baseline serum prolactin concentrations. These results have implications for maternal immunization programs designed to enhance maternal and/or infant well-being as well as other maternal health effects related to breastfeeding.

Antibody-dependent complement-mediated cytotoxicity in sera from patients with HIV-1 infection is controlled by CD55 and CD59

Various immune mechanisms have been reported to contribute to the progressive destruction of Th cells in HIV-1-infected patients. Among these, complement mediated lysis of infected cells has been suggested. An increased sensitivity of lymphocytes from HIV-1-infected patients to lysis by monoclonal antibodies directed to MHC class I antigen and complement has been directly correlated with a decreased expression of the decay accelerating factor (CD55). It also has been reported that the expression of the membrane inhibitor of reactive lysis (CD59) is decreased during HIV-1 infection. We examined the effect of antibodies in the serum of HIV-1-positive individuals and normal human serum (NHS) as source of complement on several HIV-1-infected cell lines differing in their expression of CD55 and CD59. When HIV-1-infected target cells without membrane expression of CD55 and CD59 were used, a highly significant cytotoxic effect was observed in the presence of heat inactivated anti-HIV-1-positive sera and NHS, while heat-inactivated anti-HIV-1-negative sera and NHS were unable to induce cytolysis. Similar results were obtained using purified IgG isolated from HIV-1-positive sera and either NHS or guinea pig serum as source of complement. Lysis of HIV-1-infected cells correlated with expression of viral antigens on the cell surface. HIV-1-infected CD55 and CD59 positive target cells showed specific lysis, when the function of these molecules was abrogated by blocking antibodies to CD55 and CD59. The finding of anti-HIV-1-specific cytotoxic antibodies in sera from HIV-1-infected patients should be considered in the pathogenesis of the HIV-1-infection.

Comparison of gavage, water bottle, and a high-moisture diet bolus as dosing methods for quantitative D-xylose administration to B6D2F1 (Mus musculus) mice

Gavage, water bottle, and diet incorporation are 3 dosing methods used orally to administer test compounds to rodents. These 3 methods were compared in mice to determine which represented the most quantitative delivery system. For dietary incorporation, a high-moisture bolus form of NIH-31 rodent meal was developed using hydroxypropyl methylcellulose as an autoclave-stable binding agent. A high-moisture bolus was selected to increase the acceptability of the dosed diet and to promote quantitative consumption through reduced wastage. The test compound used was D-xylose, a pentose sugar that may be quantitatively detected, colorimetrically, in urine following oral dosing. Six male and 6 female B6D2F1 mice were placed in metabolism cages and dosed with a known quantity of D-xylose by each of the 3 methods. Urine was collected before and after each method of administration and analysed for total D-xylose; the per cent recovery was based upon the amount of D-xylose consumed. Quantitative consumption was apparently greatest for water bottle dosing with an average recovery of 56.0% of the original D-xylose dose. High-moisture bolus incorporation ranked second with 50.0% D-xylose recovery, and gavage was third with 41.0% D-xylose recovery.

Dextran sulphate reduces diphenylhexatriene anisotropy in human peripheral blood lymphocytes: impact on plasma membrane fluidity and HIV-cytopathogenicity

Cytopathogenicity of HIV and other enveloped viruses is reduced by membrane fluidizing agents and by dextran sulphate (DS). To investigate whether DS exerts its antiviral action via plasma membrane fluidization of host cells, we performed anisotropy measurements on human peripheral blood lymphocytes (PBL) using the fluorescent marker diphenylhexatriene. Anisotropy was decreased in DS-exposed PBL indicating increased fluidity in the hydrophobic membrane interior.

Isolation of normal human follicular dendritic cells and CD4-independent in vitro infection by human immunodeficiency virus (HIV-1)

Immunohistological and electron microscopy studies of lymph nodes from patients infected with the human immunodeficiency virus 1 (HIV-1) demonstrated that follicular dendritic cells (FDC), the antigen-presenting cells of the B cell system, contain and may produce the virus. To elucidate the mode of infection of FDC with HIV-1 in vitro we developed an improved method for the preparation of single-cell suspensions of viable FDC with high purity (greater than 90% FDC). These isolated FDC were subjected to human T cell leukemia virus IIIB infection, which was monitored after 4 days in culture using the polymerase chain reaction. We were able to demonstrate that normal human FDC are highly susceptible to infection by HIV-1. Inhibition experiments with the monoclonal antibody OKT4a demonstrate that this infection is independent of the CD4 molecule.

Decreased binding of HIV-1 and vasoactive intestinal peptide following plasma membrane fluidization of CD4+ cells by phenytoin

Plasma membrane fluidity of intact peripheral blood lymphocytes (PBL) of phenytoin-treated nonepileptic patients and phenytoin-treated CD4+ lymphoid cells H9 and K37 was determined by fluorescence anisotropy measurements. Anisotropy values of the membrane probe 6-(9-anthroyloxy) stearic acid were decreased in all cell types as compared with controls, indicating increased plasma membrane fluidity of phenytoin-treated cells. Specific binding of 125I-labeled vasoactive intestinal peptide (VIP) to its cellular receptor CD4 on PBL was decreased in PBL of phenytoin-treated patients as compared with untreated, healthy subjects. Adsorption of a different ligand to the CD4 receptor on PBL, the human immunodeficiency virus type 1 (HIV-1), was likewise abolished to PBL of phenytoin-treated patients and phenytoin-treated CD4+ H9 and K37 cells, as assessed by indirect immunofluorescence. Subsequent HIV-1 infection of phenytoin-treated H9 and K37 cells was reduced as measured by indirect immunofluorescence and p24 antigen production. These data indicate that CD4 receptor availability for VIP and HIV-1 was reduced in phenytoin-treated cells. Using the DNA-specific dye Hoechst 33258, we examined cell cycle phase distributions of HIV-1 adsorbing and nonadsorbing H9 cells, as separated by flow cytometry. The majority of HIV-1 adsorbing cells were found to be in the G2/M phase, while nonadsorbing cells were mainly in the G0/G1 phase, during which plasma membrane fluidity is supposed to be increased. This study indicates that plasma membrane fluidization by phenytoin may serve to disrupt CD4 receptor function and emphasizes the impact of plasma membrane properties on HIV-1 adsorption and infection.

Effects of membrane lipid and fluidity modifications on HIV-1 infectibility of primate lymphocytes in vitro

Although most non-human primates, except the chimpanzee and the gibbon in vivo are not infectible by HIV-1, lymphocytes of several of these species can be infected by HIV-1 in vitro. In order to investigate whether the in vitro infectibility of primate lymphocytes might be attributed to plasma membrane adaptation processes or to serum factors, we compared HIV-1 infectibility of cultivated peripheral blood lymphocytes of macaques and of baboons on day one and on day ten of cultivation. These data were correlated to plasma membrane lipid composition and membrane fluidity. We found a correlation between increased HIV-1 in vitro infectibility and changes in plasma membrane lipid composition resulting in decreased membrane fluidity of cultured primate lymphocytes.

Decreased plasma membrane fluidity of peripheral blood lymphocytes after diethyldithiocarbamate (DTC) therapy in HIV-infected patients

In seeking the putative mechanism of action of diethyldithiocarbamate (DTC) on the immune status of HIV infected patients, the plasma membrane fluidity of peripheral blood lymphocytes (PBL) from DTC-treated and untreated patients (CDC III-IVc1) was determined. Anisotropy values of the fluorescent probe 6-(9-anthroyloxy) stearic acid were increased in DTC-treated patients (0.175 vs 0.161), indicating decreased PBL plasma membrane fluidity. The membrane rigidifying effect was significantly greater 4 h after i.v. drug administration (0.185 in treated patients). As the membrane fluidity and the function of membrane embedded antigen are interdependent, it is possible that alterations in biophysical and/or biochemical properties of membranes may account for the beneficial effect of DTC on the immune function and clinical status of HIV infected patients.

Diphenylhydantoin (DPH) blocks HIV-receptor on T-lymphocyte surface

Previous reports have shown the capacity of diphenylhydantoin (DPH) to attach to the membranes of lymphatic cells as a hapten and thus exert an unspecific influence on their ability to express certain recognition molecules. This led us to the hypothesis, that DPH might as well serve to manipulate the t-helper-lymphocytes in a way that the mode of infection of these cells by the HIV might be blocked. In order to verify this hypothesis, we exposed normal control lymphocytes as well as lymphocytes from DPH-treated patients (3 X 100-150 mg DPH/day, Phenhydan, for a minimum of 10 days) to radioactively labeled HIV (125I). Remaining radioactivity was assessed using a gamma-counter and measured 64.000-92.000 counts/min (n = 24, mean 80.000) for the control lymphocytes, while remaining radioactivity for the DPH-treated lymphocytes ranged between 2000 and 7000 counts/min (n = 24, mean 4.000, p less than 0.001). These results and similar experiments obtained with FITC-labeled HIV led us to the conclusion that DPH inhibits HIV recognition of T-lymphocytes and therefore might be used in therapy and prophylaxis of AIDS.