Ultrastructural aspects of antibody plaque-forming cells from clinically normal and overtly autoimmune NZB mice.

By B. V. SIEGEL, R. E. BROOKS AND JANE I. MORTON N E\V ZEALAND BLACK ( NZB ) MICE spontaneously develop autoimmune disease characterized by a high incidence, with age, of Coombs positive hemolytic anemia.1’2 NZB mice also differ quantitatively from “nonautoimmune” mouse strains in their responses to foreign antigenic stimuli. For example, Playfair and Evans, Williamson and Irvine4 have described an unusually early development of immune reactivity to sheep red blood cells ( SRBC ) in NZB mice, fiveto seven-day-old animals showing near-adult levels of antibody formation. Morton and Siegel2’5’#{176} have observed this relative hyperactivity to SRBC also to pertain to sixto 18-week-old NZB mice. Elevated responses in young adult NZB mice have also been reported to such antigens as egg albumin and bovine gamma globulin,7 and to bovine serum albumin,5 accompanied by an inability to induce high-dose tolerance. In contrast, old overtly autoimmune NZB mice show depressed primary antibody