Two new virus isolates, one from a California sea lion (Zalophus californianus californianus) and the other from a northern fur seal (Callorhinus ursinus) were partially characterized. Their physicochemical characteristics were similar to those of vesicular exanthema of swine virus (VESV) and San Miguel sea lion virus (SMSV). The virion morphology was in both instances typically calicivirus. On the basis of this and the serum cross-neutralization testing, these isolates were classed as two new types of SMSV and were designated serotypes SMSV-4 and SMSV-5.

Antigen capture enzyme-linked immunosorbent assay was compared to coagglutination and counterimmunoelectrophoresis for the detection of meningococcal, Haemophilus, and pneumococcal antigens. Enzyme-linked immunosorbent assay detected 1 ng of purified meningococcal and Haemophilus polysaccharides per ml and 5 ng of pneumococcal polysaccharide per ml; coagglutination detected 20, 25, and 30 ng/ml, respectively, of these polysaccharides; and counterimmunoelectrophoresis detected 10, 50, and 60 ng/ml. Double-antibody sandwichantiglobulin enzyme-linked immunosorbent assays, which employed antibodies produced in two animal species, differentiated 100% of the cerebrospinal fluid (CSF) specimens from meningococcal meningitis patients and 95% of the CSFs from Haemophilus patients from heterologous control CSFs. Double-antibody sandwich procedures, which use the same antiserum preparation for coating the wells of microtiter plates and for alkaline phosphatase-conjugated immunoglobulin, differentiated meningococcal CSFs from control specimens but were unable to effectively differentiate the Haemophilus or pneumococcal specimens from control CSFs. Coagglutination detected specific antigen in 92% of the meningococcal CSFs, 80% of the Haemophilus CSFs, and 92% of the pneumococcal specimens. The comparable percentages for counterimmunoelectrophoresis were 76, 95, and 71%.

A cell line producing monoclonal antibodies directed against a lipopolysaccharide component of Neisseria meningitidis group A has been established. These antibodies reacted with only one of three lipopolysaccharide serotyping strains of group A meningococci by coagglutination, enzyme-linked immunosorbent assay, and Western blotting techniques. A Western blot analysis showed that a NaOH digest of lipopolysaccharide was detectable by the serotype-specific antibody. The monoclonal antibodies cross-reacted with a group B meningococcal strain in an enzyme-linked immunosorbent assay. The immunoblotting analysis also showed that these antibodies reacted with the lipopolysaccharides of a group B meningococcus as well as Haemophilus influenzae type B, but not with the lipopolysaccharides of several strains of Salmonella typhi, Escherichia coli, Streptococcus pneumoniae, and Neisseria gonorrhoeae.

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