[Comparative evaluation of neurovirulence of domestic and foreign live mumps vaccine]. / Sravnitel'naia otsenka neirovirulentnosti otechestvennoi i zarubezhnykh zhivykh parotitnykh vaktsin.

Morphological and immunofluorescent study of changes in the central nervous system of monkeys with mumps was carried out in order to determine the criteria of neurovirulence of different mumps virus strains. Quantitative evaluation showed a lower residual neurovirulence of L-3 strain vs. Jeryl Lynn and Urabe Am9 strains. Use of new methodological approaches to evaluation of mumps vaccine strain neurovirulence will improve the safety control of live mumps vaccines.

[A morphological and immunofluorescent study of the measles vaccinal process in an experiment on monkeys]. / Morfologicheskoe i immunofliuorestsentnoe issledovanie korevogo vaktsinal'nogo protsessa v éksperimente na obez'ianakh.

A correlation between localization of morphological lesions and the presence of viral antigen in the CNS was established. Dissemination of the infectious process in the CNS depended on both topography of the inoculated areas and more so on traumatic injury of the ventricular system. Viral antigen could be detected in the reticuloendothelial system and epithelial cells of the respiratory tract without inducing specific cytopathic changes. Simultaneous morphological and immunofluorescent examination allowed the safety of live measles vaccine to be established more accurately.

Pathomorphologic characterization of CNS damage in monkeys infected with persistent variant of measles virus vaccine strain L-16.

The lesions of CNS were examined in monkeys infected intracerebrally (i.c.) with a variant of measles virus vaccine strain L-16 isolated after prolonged persistence in human cell culture NEr-2. The persisting virus variant appeared pathogenic for monkeys. The changes which had developed in their CNS within 30 to 60 days post-infection (p.i.) were alike to acute measles encephalitis which was evidenced by giant cell formation at the injection site. Twenty-two months p.i. the chronic character of lesions was evident from the appearance of foci of neuron destruction. Based on morphologic findings it was suggested that strain L-16-H has acquired some properties characteristic of nonattenuated virus.

Reproduction of human and animal influenza viruses in human nasal polyp organ cultures.

Human influenza virus strains were easily grown and passaged in human nasal polyp organ cultures causing marked damage of the epithelium. Unlike to human strains, the animal influenza virus strain could be propagated for no longer than 2 or 3 passages and even the 1st passage failed to cause significant morphological changes of the epithelium cells.

Study of mumps virus invasiveness in monkeys.

Invasiveness of mumps virus strains, differing in the degree of attenuation was studied in green and Macaca mulatta monkeys infected either into salivary glands or intramuscularly. Peripheral infection with all strains under study resulted in their penetration into CNS irrespective of the attenuation degree. Specific morphological changes were observed in the brain of monkeys as confirmed by detection of virus antigen using fluorescent antibodies (FA) staining. Morphological changes and time of virus antigen detection in the brain differed depending on the neurovirulence of the strains based on different degree of their attenuation.

Effect of immunosuppression on morphological changes in CNS of monkeys infected with different measles virus vaccine strains.

Residual neurovirulence of measles virus vaccine strains "Leningrad-16", "Moscow-5" and of cloned variant of L-16 strain--clone 3, differing in the degree of attenuation, was studied in intracerebrally (i.c.) infected Cercopithecus aethiops monkeys, receiving cortisone and/or antilymphocyte serum (ALS). Whereas the sensitivity for detection of the potential neurovirulence of vaccine strains was not increased by cortisone treatment. ALS had such effect in detection of neurotropic properties of the L-16 strain and its cloned variants.

[Persistence of the measles antigen in the central nervous system of monkeys infected with clonal variants of the L-16 vaccinal strain of the measles virus]. / Izuchenie persistentsii korevogo antigena v tsentral'noi nervnoi sisteme obez'ian pri infitsirovanii klonovymi variantami vaktsinnogo shtamma L-16 virusa kori.

The time of persistence of measles antigen was studied in Macaca mulatta and green monkeys inoculated intracerebrally with the vaccine L-16 strain of measles virus and its two genetically homologous variants. Two clones differing in their neurovirulence were used. The results of the study showed correlation between the time of the antigen persistence in the central nervous system and the severity of morphological changes.

The replication of influenza A viruses in organ cultures of human nasal polyps.

Organ cultures of human nasal polyps were shown to support the replication of five out of seven human influenza A viruses and three out of six avian strains with varying degrees of efficiency. The ability to replicate was independent of the antigenic formula of the virus. The structure of nasal polyps closely resembled that of normal nasal mucosa and infection with influenza A virus resulted in histological changes analogous to those seen in natural infections. This system provides an in vitro method for more detailed studies of influenza A virus and possibly other respiratory virus infections of man.

Morphological characterisitcs of the pathological process in the central nervous system of monkeys infected with variants of measles virus strain L-16.

The neurovirulence of L-16 vaccine measles virus strains and its 9 clonal variants was investigated in intracerebrally infected Macaca mulatta monkeys. Two groups of clones were distinguished: one comprised variants that caused destructive changes of neurons in the brain and diffuse proliferative gliosis, and the second variants that caused changes of a transitory character, connected with the traumatic exposure.