Resistance to Microbial Infection ‐ Vaccines in Theory and Practice

Vaccination Against Experimental Staphylococcosis in Sheep ‐ Observations on Bacteriology and Pathology Following Challenge

“…O n the other hand the survival data for Group 3 sheep (live vaccine) suggests that these animals were better protected than animals in Groups 1 or 2 during the period 50 t o 90 days post-imrnunisation. Such a resuIt would be consistent with some form of specific cell-mediated immunity operating in Group 3 animals, a finding already associated with live vaccination when facultative intracellular bacteria are used (Mackaness 1971;Woolcock 1973).…”

Vaccines and cell-mediated immunity.

“…Although it is generally agreed that live attenuated vaccines induce a highly effective type of immune response (53,116,248,264), this type of preparation is not yet commercially available for the prevention of enteric disease in humans. Several experimental vaccines have been developed recently (4,76,85) but are still in the initial stages of assessment in human populations (86).…”

“…Circulating specific immunoglobulins undoubtedly do protect the host effectively against many infectious agents, especially those caused by the toxigenic microorganisms, some of the viruses, and the obligate extracellular parasites such as Diplococcus pneumoniae (75) and Pasteurella multocida (17,58). However, there is no indication that humoral factors alone can prevent such diseases as listeriosis, tuberculosis, brucellosis, or salmonellosis, in either actively or passively protected animals (152,154,165,264). The inability of passively introduced antibody to protect mice against salmonellosis has been ascribed to the use of insufficient amounts of hyperimmune serum (127).…”

An enzyme‐linked immunosorbent assay for detection of Brucella abortus in cattle using monoclonal antibodies

“…However, in contrast to the CFT, high numbers of positive reactions to both ELISA tests occurred in the cattle in groups 1 and 2 that were challenged but uninfected and to a lesser extent those cattle in group 3. This suggests that proliferation of the challenge inoculation (especially in the pregnant animal) resulted in some antibody production before the immune system mounted an effective bactericidial (T-cell mediated) response (Woolcock 1973). The fact that some of these animals vaccinated or "naturally immune" were to eliminate the infection completely should not reduce the value of any test designed to detect antibody, because at the time samples were taken there was no way of knowing which animal would succeed in eliminating the infection and which would abort.…”