Subsequent Endotoxin Challenge Research Articles

Endotoxin lethality and tolerance in mice: analysis with the B-lymphocyte-defective CBA/N strain

Immune-defective and immunologically normal F1 mice derived from the CBA/N strain were used to study the influence of anti-endotoxin antibody on the lethal effects of endotoxin. Immune-defective F1 male mice were unable to make specific responses to purified preparations of E. coli O111:B4 endotoxin, whereas their immunologically normal F1 female littermates made excellent responses. The ability to form antibody to lipopolysaccharide (LPS) in these F1 mice did not influence either their natural resistance to endotoxin challenge or the effects of pretreatment with sublethal amounts of endotoxin on subsequent challenge with higher normally lethal doses. Furthermore, transfer of sera with high titers of anti-LPS antibody to mice prior to challenge with LPS failed to protect. Thus, anti-LPS antibody does not appear to play a critical role in protection of immune-defective (CBA/N X DBA/2) F1 male mice to the lethal effects of endotoxin or to the protective effects of a single sublethal dose of endotoxin on subsequent endotoxin challenge.

Modification of lethality of endotoxin in mice by zymosan.

SummaryPre-treatment of mice with different preparations of zymosan modified the lethal effect of a subsequent endotoxin challenge, ranging from increased resistance to increased susceptibility, despite equivalent RES stimulation. Source and degree of heating in preparation for injection were determinants. Greater relative sensitivity to i.v. than to i.p. challenge was found regardless of the zymosan used. Protection was not attributable to endotoxin contamination or to stimulation of serum antibody titer to the challenge. Zymosan produced a monophasic fever in the rabbit, differing from the biphasic endotoxin fever, and did not elicit an acute leucopenia.