Polypeptides of mumps virus.

Mumps virus was propagated in the extra-embryonic fluids of embryonated chicken eggs and was labeled by cionjection of radioactively labeled amino acids. The virus was purified by density gradient centrifugation, and its polypeptides were analyzed by polyarylamide gel electrophoresis. The virus was found to be composed of six polypeptides, ranging in size from 40,000 to 64,000 daltons. Viral proteins 1 and 3 were the glycoproteins of the virons. When the virus particle was treated with noniontic detergents, a small fraction of these glycoproteins could be released into the supernatant. After treatment with nonionic detergents in high salt and alkaline conditions, more of the surface glycoproteins were removed. This treatment also released the smallest viral polypeptide from the virion. The glycoproteins were separated using an affinity chromatographic column of agarose-fetuin. The heavier glycoprotein, viral protein 1, was found to contain both the neuraminidase and hemagglutinating activity. The two glycoproteins were tested for their ability to react in complement-fixing tests with mumps antisera. Only the heavier glycoprotein reacted with antisera possessing both anti-S and anti-V activity. Neither glycoprotein reacted with antisera specific for the S antigen. Thus, it was concluded that this glycoprotein corresponds to the classical V antigen of mumps virus.     

Epidemic of mumps in a partially immune population.

The incidence of mumps in vaccinated and nonvaccinated schoolchildren was studied after a recent epidemic. Information was collected by telephone interviews with the parents and a review of the physicians'' records. The vaccine appeared to be effective, for the incidence of mumps in the 145 vaccinated children--5.5%, or 8 cases--was significantly less (P less than 0.001) than the incidence in the 350 children considered susceptible to infection--21.7%, or 76 cases. The percentage of children who had been immunized decreased with increasing age, and acquisition of immunity through natural infection had the reverse trend; thus, the proportions of children susceptible to infection in each age group were about the same, and the age-specific attack rates were similar. Although the mothers were accurate in indicating absence of vaccination, they incorrectly indicated vaccination of their children 43.0% of the time; this error in reporting could influence vaccine administration in older children. Our findings suggest that mumps vaccination may substitute for natural illness in immunizing populations, and that more extensive use of the vaccine over a broader age range is required to prevent similar epidemics in the future.     

Evaluation of the neurovirulence test for mumps vaccines.

Neurovirulence tests in Macaca fascicularis using commercial preparations of different vaccine bulks and a wild-type strain revealed that the test was unable to distinguish mixed from pure populations or a suitable vaccine from a related strain which has been shown to be associated with clinical meningitis. However, the test was able to distinguish a wild-type strain from the vaccine strains successfully. The ability of the test to discriminate between acceptable and unacceptable seeds requires further examination.