title: The lipopolysaccharide polyclonal response is a function of the background response.
abstract: The aims of this report are: to investigate the kinetics of the E. coli lipopolysaccharide polyclonal response as a function of the background response, to test the capacity of lipopolysaccharide to activate presumably resting memory cells for IgM. Because mice do not produce a plaque-forming cell background against rat erythrocytes, the mouse-rat erythrocyte system was chosen. Random bred Swiss albino mice, aged 2-3 months, were inoculated with rat erythrocytes (5 X 10(5)/mouse) and the course of the plaque response was followed up; no response was detected on day 0, it rose sharply up to day 4, dropped abruptly between days 4 and 7 and trailed off afterwards to disappear by day 29. As to the lipopolysaccharide-triggered anti-rat erythrocyte response, lipopolysaccharide (100 micrograms/mouse) was inoculated on days--3, 1, 4, 7, 18 and 29. post-rat erythrocytes and the responses were measured 3 days after lipopolysaccharide inoculation. The curve paralleled that of the antigenic response, although at a higher level; thus, both the specific and the polyclonal responses followed the same kinetics. At one month post-rat erythrocyte priming, the animals displayed a background comparable to that of naive mice, although their IgM response to a booster (2 X 10(7) erythrocytes, iv) was faster and greater (p less than 0.01) than the primary response to the same dose; i.e., there was IgM memory. Nevertheless, lipopolysaccharide stimulation (100 micrograms/mouse, ip) of primed animals gave a response comparable (p greater than 0.10) to that of naive mice; i.e., lipopolysaccharide alone was unable to elicit a secondary-like response.
mesh_terms: D000818:Animals; D000917:Antibody Formation; D000921:Antibody-Producing Cells / Q000276:immunology; D002999:Clone Cells / Q000276:immunology; D004912:Erythrocytes / Q000276:immunology; D004926:Escherichia coli / Q000276:immunology; D005260:Female; D007075:Immunoglobulin M / Q000096:biosynthesis; D007156:Immunologic Memory; D008070:Lipopolysaccharides / Q000276:immunology*; D008297:Male; D051379:Mice; D051381:Rats
chemical_list: D007075:Immunoglobulin M; D008070:Lipopolysaccharides