Nonspecific resistance to Escherichia coli in mice

Staphage lysate: an immunomodulator of the primary immune response in mice

The immunological enhancing activity of staphage lysate on the primary immune response of mice as reflected by specific heteroantibody production to a single antigenic stimulus and on immunoglobulin synthesis was determined. Staphage lysate was administered at different periods in relation to time of sheep erythrocyte injection so that both the inductive and the productive phase of the immune response could be evaluated. Treatment with staphage lysate induced pronounced enhancement of the hemagglutinin response by day 14 regardless of the dose or the time of its administration. Significantly higher antibody levels in the test groups were observed when compared with the control animals, peak antibody titers being 21 days following antigenic challenge. Furthermore, staphage lysate administered without an accompanying antigen evoked a heightened serum immunoglobulin level in mice for a period of more than 14 days after injection. IgG1, IgG2a and IgG2b were significantly elevated as a direct result of this treatment. This increased output of immunoglobulin synthesis and heightened hemagglutinin titers demonstrate that staphage lysate is not only an immunomodulator of cell-mediated immunity, as previously reported, but also an effective immunoadjuvant of the humoral antibody response capability in the host.

Specific and nonspecific immune resistance enhancing activity of staphage lysate

The immunopotentiating activity of staphage lysate (SPL) was evaluated in terms of its immune protection against lethal bacterial infection and its antitumor activity. Mice were pretreated weekly with 10(8) viable, Staphylococcus aureus, strain 18Z for 3 weeks (Induction), followed by intraperitoneal SPL injections (Elicitation) at various times in relation to infectious challenge or tumor implantation. Induction without elicitation, or elicitation alone failed to provide protection against Klebsiella pneumoniae infection and resulted in only 30-40% survival against homologous infection with pathogenic S. aureus type III, whereas combined induction and elicitation produced enhanced resistance induction and elicitation regimens resulted in 50% and 80-100% survival in mice inoculated with K. pneumoniae and S. aureus, respectively. SPL had no antitumor effect in mice implanted with median survival time resulting from induction and elicitation in animals implanted which Ehrlich's ascites. This enhancement of immune resistance may possibly be related to activation of thymus-modulated lymphocytes and macrophages by SPL.