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Biomedical subjects

A E Beer

Publications and source records attributed to A E Beer.

16 recordsLinked to original sources
PubMed1979

In vitro stimulation of human colostral lymphocytes by cytomegalovirus.

Lymphocytes isolated from the peripheral blood and colostrum of 17 healthy donors, 1 to 3 days post partum, were cultured with cytomegalovirus (CMV), strain AD169, as stimulating antigen in a lymphocyte transformation test. The test was performed in microculture utilizing the cell-free supernatant of CMV-infected human fibroblasts and isolated peripheral blood and colostral lymphocytes showing normal reactivity to phytohemagglutinin. Lymphocytes from CMV-seropositive donors were stimulated by the CMV antigen, whereas lymphocytes from both male and female CMV-seronegative donors failed to respond, as measured by incorporation of tritiated thymidine. In those donors from whom utilizable colostrum samples were obtained, two donors lacking peripheral blood lymphocyte (PBL) CMV reactivity also lacked colostral lymphocyte CMV reactivity. The remaining five colostrum donors showed both PBL and colostral lymphocyte reactivity to the CMV antigen, with colostral lymphocyte reactivity in four of five donors exceeding PBL-cytomegalovirus reactivity. There was no clear-cut correlation between the titer of CMV antibody by complement fixation and the amount of tritiated thymidine incorporated into the lymphocytes stimulated with the CMV antigen. These results highlight current knowledge that milk and colostrum contain large numbers of specifically sensitized T-lymphocytes, expressing a selective quota of maternal cell-mediated immunities. We are currently investigating the possibility that CMV-reactive colostral lymphocytes obtained during suckling may be of some protective value to the immunologically inexperienced neonate by transferring an adoptive immunity. This assumes special significance in the light of known transmission of CMV via mothers' milk to neonates.

Antigens, Viral↗
PubMed1979

Analysis of complement receptors on B-lymphocytes in human milk.

Experiments were performed on human B-lymphocytes in paired samples of milk and blood from the same patient to determine the numbers and percentages of lymphocytes with complement receptors, utilizing the erythrocyte-antibody-complement (EAC) rosette assay. Studies on nine paired samples show the numbers, as well as the percentages, of complement-reactive cells (CRCs) in milk are significantly lower than in blood. Milk lymphocytes were cultured in media containing serum for a 24 hour period to determine if the observed lower numbers of CRCs in milk were due to saturation of the lymphocyte receptors with free complement, as well as to determine if the culture of the cells in nutrient media might result in the reformation of shed complement receptors. Similarly, peripheral blood lymphocytes were incubated in milk supernatant to determine if free complement or other factors in milk might interfere with the EAC assay. These studies support previous findings from this laboratory that B-lymphocytes in milk represent a subpopulation of cells different from those in peripheral blood. The paucity of B-lymphocytes bearing complement receptors in milk may be due to the following: (1) B-lymphocytes in milk may be plasmablasts and/or antibody-producing plasma cells--both known to lack complement receptors; (2) selective processes operating at the mammary alveolar epithelium allowing transit of certain subclasses of maternal immunoglobulins may also allow transepithelial passage of B-lymphocytes with surface immunoglobulins, but no complement receptors. These possibilities are currently being studied.

Antibodies↗
PubMed1978

Adipose tissue, a neglected factor in aetiology of breast cancer?

The abundant adipose tissue that intimately invests both the alveolar and the ductal epithelium of the mammary gland may function as a slow-release depot for lipid-soluble carcinogenic agents of both endogenous and exogenous origin taken up from the bloodstream.

Adipose Tissue↗
PubMed1978

Maternal immunological recognition mechanisms during pregnancy.

One of the most intriguing shortcomings of modern immunology, especially transplantation immunology, is its failure to provide a satisfactory final explanation for the consistent non-rejection of immunogenetically alien conceptuses in utero, even in specifically preimmunized females. Certainly, there is no shortage of hypotheses. Over the past few years various observations have utterly refuted the simplistic notion that the much-mated but nulliparous or gravid females are immunologically unaware of the presence and activities of allogeneic cells transiently or chronically within their reproductive tracts. This evidence has engendered the belief that some kind(s) of active response(s) on the part of the female, following early recognitive events, plays an important, if not essential, role, in conjunction with adaptive hypoantigenicity of the trophoblast, not only in conferring selective benefits upon the conceptus from the time of implantation, but also in affording it protection from the possible hazards of a cellular immunity. Evidence is emerging that during mating, implantation, placentation, and gestation (1) various fetal and histocompabibility antigens are presented to the mother in a unique manner; (2) she does respond to these; and (3) her responses aid in the establishment and maintenance of a harmonious state of immunological coexistence with her fetus. There are reasonable grounds for believing that a complete understanding of the immunobiology of the maternal-fetal relationship may facilitate significant advances in both transplantation and tumour immunology.

Animals↗
PubMed1977

Colostral cell-mediated immunity and the concept of a common secretory immune system.

Historically colostrum and milk have been thought to confer immunity on the neonate only by virtue of their immunoglobulin content. Recently we have observed that colostrum also contains viable T lymphocytes capable of expressing cell-mediated immunity in vitro and have employed techniques of lymphocyte culture to elucidate the local nature of mammary tissue immunity at the T-cell level. The results indicate that the activity of colostral lymphocytes appears not to represent the total immunological experience of the mother but that they may contain reactive clones beneficial for the suckling. Colostral immunity appears to depend upon sensitizing events within the intestine and respiratory tract, followed by the migration of lymphoid precursors to the breast, suggesting a relationship between the expression of immunity at various secretory surfaces.

Animals↗
PubMed1977

Pathogenesis of Rh immunization in primigravidas. Fetomaternal versus maternofetal bleeding.

Rh immunization occurring during a first pregnancy with no history of preceding abortion or transfusion may result when Rh incompatible fetal to maternal bleeding ensues early enough in the gestation to initiate a maternal immune response before parturition. Alternatively, the initial antigenic stimulus could be the consequence of maternal to fetal transfer of Rh-incompatible erythrocytes while the patient herself was in utero or at the time of her own delivery. These hypotheses were tested by 1) analysis of the blood group and Rh of 22 Rh-immunized primigravidas, their infants, and their own mothers; 2) comparison of the number of fetal cells in the maternal circulation during the antepartum period in 20 women at high risk for fetal to maternal bleeding with their matched controls; and 3) Rho (D) antibody determinations in 70 Rh-negative infants born to Rh-positive mothers. The results indicate that antepartum fetal to maternal bleeding is the usual cause of Rh immunization in primigravidas, and the Rh-negative woman with blood group A, B, or AB who gestates an ABO-compatible Rh-positive male is at highest risk. The antepartum use of anti-Rho (D) immune globulin has potential prophylactic value in this situation.

ABO Blood-Group System↗
PubMed1976

In vitro studies on the T-lymphocyte population of human milk.

Human milk lymphocytes (ML) can be partially purified and propagated in vitro as a means of assessing their immunological function. When exposed to a variety of stimuli known to activate T lymphocytes, ML respond in a unique manner that indicates a selected population of immunocompetent cells. ML are hyporesponsive to to nonspecific mitogens and respond in a reduced manner to histocompatibility antigens on allogeneic cells. In most cases, they are completely unresponsive to C. albicans although blood lymphocytes from the same patients respond to the antigen. The Kl capsular antigen of E. coli induces significant proliferation in lymphocytes obtained from milk, but fails to stimulate blood lymphocytes. This dichotomy of reactivity does not appear to result from suppressive factors or cells in milk or insufficient adherent cell function. Rather it appears to reflect the accumulation of particular lymphocyte clones in the breast and the local nature of mammary tissue immunity at the T-lymphocyte level.

Antigens, Bacterial↗
PubMed1976

Immunogenetic factors in preeclampsia and eclampsia. Erythrocyte, histocompatibility, and Y-dependent antigens.

Determination of ABO and HL-A antigens and sex ratio of infants born to 46 women with preeclampsia or eclampsia, in comparison with normal controls, disclosed no predominant blood group, HL-A haplotype, or qualitative difference in maternal-fetal incompatibility. These results suggest that a link between immunologic mechanisms and the pathogenesis of toxemia syndromes, if present at all, must be associated with feto-placental tissue-specific antigens.

ABO Blood-Group System↗