Jean Hamburger

Presence of antigen-antibody complexes in antiallogeneic and antixenogeneic sera.

SUMMARY Antilymphocyte sera (ALS), either allogeneic (for example, Lewis anti-August rat serum) or xenogeneic (the classic ALS), may retain the antigen used for the immunization of the animal producing the serum in the form of antigen-antibody complexes, at least when the animal is bled within the first 2 weeks following the last immunizing injection. Evidence for this has been obtained in vivo and in vitro. In vivo experiments showed that injection of Lewis anti-August serum to a normal Lewis rat can induce a delayed active immunization against the August strain. In vitro studies proved the presence of August antigens in the anti-August sera, by precipitation of the antigen-antibody complexes with 6 M urea, removal of the antibody by filtration, and demonstration that the filtrate specifically inhibits complement-dependent cytotoxicity of anti-August antibodies. The interpretation of a number of previous works on so-called passive enhancement of grafts or on various effects of ALS may have to be reconsidered on the basis of these findings.

β glucuronidase in macrophages of skinallografted mice—II: Demonstration of a lymphokine decreasing macrophage β glucuronidase in allograft immunity

Abstract Mouse peritoneal macrophages (obtained with or without previous injection of thioglycollate) incubated for 72 hr with the supernatant of a mixed lymphocyte culture (MLC) between the donor and the recipient of a skin allograft undergo a striking decrease in their β glucuronidase content. This decrease is not due to a loss of macrophage viability. The release of the enzyme in the culture medium is somewhat enhanced, but quantitative studies show that enzyme secretion is usually not sufficient to be solely responsible for the enzyme decrease within the cell. Thus, inhibition of enzyme synthesis should be considered a serious possibility.

Macrophage arming factor release by allografted mouse lymphocytes stimulated by phytohemagglutinin.

Spleen cells from a C57BL/6 mouse allografted with DBA/2 skin may release a macrophage arming factor when stimulated with phytohemagglutinin. This in vitro nonspecific release is observed only when the recipient cells are collected during a limited period preceding or coinciding with graft rejection. The phenomenon disappears if the skin allograft has been removed before cell collection. It appears if an i.v. injection of donor cells is given to the recipient after graft removal, on the day preceding cell collection. These data suggest that this in vitro apparently nonspecific macrophage arming factor release by phytohemagglutinin-stimulated recipient cells may in fact disclose a previous specific in vivo immune cell triggering by graft antigens.

Beta glucuronidase in macrophages of skin-allografted mice--I. Decrease in beta glucuronidase in allografted mouse peritoneal cells in the presence of donor cells.

Abstract Mouse peritoneal cells collected 12 days after a skin allograft are incubated with donor-strain cells. This results in a striking decrease in their β glucuronidase activity. The phenomenon takes place in macrophages and is observed with cells obtained with or without thioglycollate intraperitoneal injection prior to cell collection. No or little alteration of acid phosphatase is observed in the same macrophages. This phenomenon is intense only when using cells bearing donor H-2 antigens as stimulator cells. However, stimulation of recipient cells by other allogenic cells with an H-2 differing both from donor and recipient induces a small degree of enzyme decrease. Treatment of peritoneal cells with anti-θ serum before adding donor cells strongly depresses the phenomenon. The observed macrophage modifications might thus result from the release of a lymphokine by recipient lymphocytes that may be found in the peritoneal cell population. Repeated intraperitoneal injections of donor cells to the allografted mouse induces a similar enzyme modification in peritoneal macrophages, but to a lesser degree.

EFFECT OF CORTICOSTEROIDS ON MACROPHAGE ARMING

Publisher Summary Normal macrophages can be rendered cytotoxic (or “armed”) when incubated with the supernatant of a mixed culture of lymphocytes from a skin allografted mouse and lymphocytes of the skin donor. The Macrophage Arming Factor (MAF) production may occur in vivo during allograft rejection. This chapter discusses the effect of corticosteroid, administered in vivo or added in vitro, on MAF production by sensitized lymphocytes and macrophage arming by MAF. The production of MAF by allografted mice spleen lymphocytes is not altered by the in vivo corticoid administration. The in vitro addition to MLC of corticoid doses—as high as 1 mg M.P. or 10 mg H.H. per ml—do not alter MAF production by sensitized lymphocytes in the presence of donor cells. Treatment of normal macrophage monolayers with corticosteroids modifies their capacity to become cytotoxic when incubated with MAF-rich supernatants. Steroids administered in vivo and in vitro do not inhibit MAF production by sensitized lymphocytes but diminish or abolish the normal macrophage capacity to become armed when treated by MAF. The effect of corticosteroid treatment on graft rejection might be partly due to the loss of sensitivity of the recipient macrophages to arming factors.