In the assessment of immunity to the encapsulated virulent strain of Klebsiella pneumoniae and its avirulent mutant defective for capsular polysaccharide (CPS), killed bacterial vaccine of both strains could protect mice equally against challenge with 100 x LD50 of encapsulated wild strain. Antisera to each strain conferred the same level of protection on naive mice upon transfer; the protective anti-mutant serum was highly capable of opsonizing the encapsulated bacteria. In addition to the common antigenic components shared by both strains, the wild strain had antigen(s) unrelated to the mutant since the protective capacity of the anti-wild serum was not affected by preabsorption with the mutant strain; the protection conferred by the anti-mutant serum was mediated by antibodies against non-capsular antigens since the antiserum did not contain antibodies against purified CPS detectable by ELISA. As possible candidates among the non-capsular antigens, outer-membrane proteins (OMPs) extracted from the mutant strain were examined for their immunogenicity. Immunoblotting of the protein-containing fraction and ELISA using LPS-free OMP suggested that a number of proteins were involved in the immune response evoked by K. pneumoniae. Furthermore, mice immunized with OMP or anti-OMP serum could overcome a lethal challenge with the wild strain. These results indicated that OMPs of K. pneumoniae are implicated as the protective antigens and may pave the way for the development of non-capsular, proteinaceous vaccines.

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The role of gamma interferon (IFN-gamma) in an increase in Ia-bearing macrophages during Listeria monocytogenes infection was studied. The peritoneal macrophages from L. monocytogenes-infected mice contained a high proportion of Ia. Intraperitoneal injection of the supernatant from a culture of spleen cells from L. monocytogenes-infected mice induced Ia-rich exudates in normal mice. The Ia-inducing activity in the culture supernatant was abrogated by the pretreatment of spleen cells with anti-Thy-1.2 antibody plus complement. Immunoadsorption of the culture supernatant with anti-recombinant IFN-gamma antibody and protein A-Sepharose CL-4B completely abrogated its Ia-inducing activity. These results suggested that an increase in Ia-bearing macrophages during L. monocytogenes infection was attributable to T-cell-derived IFN-gamma.

The effects of high-protein food on the bioavailability of both the racemate and individual enantiomers of verapamil were investigated in 12 healthy volunteers using a randomized crossover design. Food had no effect on any parameter of bioavailability for both the racemate and the individual enantiomers of verapamil except time to maximum concentration (tmax), which was significantly prolonged after food intake. The pharmacokinetics of the enantiomers of norverapamil were not significantly changed by food intake. These results suggest that high-protein food does not alter the pharmacokinetics and bioavailability of either the racemate or the individual enantiomers of verapamil. Therefore, the clinical efficacy of verapamil is not related to food intake, except for a slight prolongation in the time to onset of the pharmacologic effects. The present data can be applied to the high-protein content meal intake.