Lymphoid Cell Membranes Research Articles

Antiserum to a Soluble Lymphoid Membrane Preparation Stimulates Human Leukocyte DNA Synthesis

Summary Rabbit antiserum against soluble human lymphoid cell membrane glycoproteins containing histocompatibility (HL-A) antigens stimulated DNA synthesis in human peripheral blood leukocytes. Absorption of the antiserum with human lymphoid cells totally removed the stimulating activity. Stimulation was independent of the HL-A type of the leukocyte donor. The glycoproteins isolated from papain solubilized lymphoid membrane preparations, therefore, retain sufficient structure to serve as immunogens in the production of heterologous antisera against membrane components. Interaction of these components with antibody leads to increased DNA synthesis.

A population of lymphocytes bearing a membrane receptor for antigen-antibody-complement complexes. I. Separation and characterization.

A population of lymphoid cells from several animal species, including man, was identified through a membrane receptor which binds sheep red blood cells treated with antibody and complement. When cells from different lymphoid organs were incubated with EAC at 37 degrees C, only part of the lymphocytes (named CRL) bound EAC and formed rosettes, and this interaction was shown to be C3-dependent. Mouse lymphoid cells could be specifically depleted of CRL by allowing them first to interact with EAC and then submitting the mixture to ultracentrifugation in a gradient of BSA. After ultracentrifugation, a population of cells containing 95% or more of non-CRL were recovered from the upper layers of the gradient. In addition to their different abilities to bind EAC, CRL and non-CRL from mouse lymphoid organs could be distinguished by the following properties: (a) CRL adhered preferentially to nylon wool at 37 degrees C in the presence of mouse serum. (b) After differential flotation in a gradient of BSA, a significantly higher proportion of CRL were recovered from the upper layers of the gradient. (c) The population of CRL contained most of the lymphocytes bearing immunoglobulin determinants on their membranes. (d) The distribution of CRL was quite different among lymphocytes obtained from various lymphoid organs, and they were never found in the thymus. (e) The membrane receptor for EAC was not detected in plaque-forming cells of mice which had been previously immunized with burro red cells. CRL and non-CRL could not be distinguished by their life span, as they were found in similar proportions among long-lived and short-lived lymphocytes from mouse peripheral lymph nodes. The function of this receptor on the membrane of certain lymphoid cells may be related to (a) the trapping and localization of antigen in lymphoid organs or (b) the localization of lymphoid cells in inflammatory sites.

The Antigenic Specificity of Spermatozoa

Summary Experiments were undertaken to determine whether histocompatibility antigens were detectable on spermatozoa and whether it might be possible to differentiate spermatozoa bearing X and Y chromosomes by means of the fluorescent antibody technique. C57BL/6 female mice were immunized with skin grafts and lymphoid cells from C57BL/6 males in an attempt to produce antibody specific for Y-determined antigen(s). Despite accelerated second-set rejection of male skin grafts, it was not possible to detect antibody to Y-determined antigen in female C57BL/6 mice immunized with male tissue. It was possible to demonstrate the presence of H-2 antigens on the cell membranes of lymphoid cells but not spermatozoa by means of the fluorescent antibody technique. Using sera from both male and female C57BL/6 mice which had been immunized with sperm or testis, it was possible to demonstrate by both direct and indirect fluorescent staining techniques antibody specific for the acrosome of mouse, rat and guinea pig sperm. It is suggested that acrosomal antigen may be a cell-specific antigen of spermatozoa.