A SIMPLIFIED TISSUE CULTURE TUBE NEUTRALIZATION TEST FOR ROUS SARCOMA VIRUS ANTIBODIES

Mouse immunoglobulin antibodies require complement for neutralization of mouse retroviruses

The addition of guinea pig complement was found to enhance the neutralizing capacity of mouse antibodies directed against the endogenous ecotropic murine leukemia viruses. The same immune sera, when tested without complement, had low or negligible neutralizing capacities, regardless of whether freshly harvested, unfrozen virus was used to preserve virus infectivity. Antibodies in high titers were found in sera from NFS congenic mice carrying the mouse leukemia virus inducing locus Akv-2. These mouse antibodies were type specific and failed to neutralize either Friend or Moloney leukemia virus. The mouse serum immunoglobulin fraction containing the complement-dependent antibodies was tentatively identified as immunoglobulin M.

Oncogenes of RNA tumor viruses as determinants of cancer

Evidence from sero-epidemiological studies and from cell culture studies supports the hypothesis that the cells of many, and perhaps all, vertebrates contain information for producing C-type RNA viruses. It is postulated that the viral information (the virogene), including that portion responsible for transforming a normal cell into a tumor cell (the oncogene), is most commonly transmitted from animal to progeny animal and from cell to progeny cell in a covert form. Carcinogens, irradiation, and the normal aging process all favor the partial or complete activation of these genes. An understanding of how normal cells and normal animals prevent expression of endogenous viral information would appear to offer one of the best hopes for the control of naturally occurring cancers.

Multiple group-specific antigen components of avian tumor viruses detected with chicken and hamster sera

Multiple group-specific (gs) components of the avian leukosis-sarcoma viruses were detected by immunodiffusion (Ouchterlony) tests with sera from hamsters bearing tumors induced by sarcoma viruses and with sera from adult chickens immunized with avian sarcoma or leukosis viruses. Immune hamster sera detected up to four components, whereas chicken sera detected at least one. The hamster and chicken sera identified a similar antigen, as indicated by reactions of identity. Relatively few chicken sera containing neutralizing antibody to avian sarcoma or leukosis viruses reacted in immunodiffusion with the gs antigen. The gs components were released from the virion by various means of disruption, including freezing and thawing. Tests with tissues from normal chickens and from chickens with Marek's disease failed to demonstrate any reactions with hamster or chicken gs antiserum.

Two loci controlling genetic cellular resistance to avian leukosis-sarcoma viruses

Female chickens known to be heterozygous for resistance to subgroups A and B of the avian leukosis-sarcoma viruses were mated to males known to be homozygously resistant to both. The progeny were assayed both on the chorioallantoic membrane (CAM) and in tissue culture for resistance to representative viruses of the A, B, and tentatively defined C subgroups. Segregation ratios of resistance to A and B subgroup viruses agreed with the previously suggested hypothesis of single-autosomal-recessive genes controlling resistance to each subgroup. Mixed infection on the CAM and replicate plate infection in tissue culture with subgroup A and B viruses showed that resistance to the A and B subgroups was inherited independently. Assays with viruses tentatively classified as subgroup C indicated that they were largely composed of a mixture of subgroup A and B viruses or of particles possessing the host range specificity of both. However, virus stocks of the subgroup C category, as well as some stocks classified as subgroup B, produced small numbers of pocks or foci on individuals known to be resistant to subgroup A and B viruses. It is suggested that these Rous sarcoma virus stocks carry between 1 and 10% of a true subgroup C virus.

Complement-fixing antigens in hamster tumors induced by the Bryan strain of Rous sarcoma virus

Hamster tumors transplanted subcutaneously from primary intracranial tumors which developed after inoculation of the Bryan strain of Rous sarcoma virus, contained virusspecific tumor antigens indistinguishable from those induced by the Schmidt-Ruppin strain.

Brain Tumors (Gliomas) Induced in Hamsters by Bryan's Strain of Rous Sarcoma Virus

Gliomas and choroid plexus papillomas were induced by intercerebral inoculation of Rous sarcoma virus, Bryan's strain, in newborn hamsters. Of five pools of virus tested, four were effective when used at high dose.

Complement-Fixing Antigens in Tissue Cultures of Avian Leucosis Viruses

Avian sarcoma and leucosis virus preparations grown in chick embryo tissue cultures contained complement-fixing antigens, which were demonstrated with the use of antiserums from hamsters carrying sarcomas induced by the Schmidt-Ruppin strain of avian sarcoma virus. The complement-fixing antigens shared by three different strains of avian leucosis and one strain of avian sarcoma viruses were largely "soluble" (having failed to sediment when centrifuged at 59,364g for 70 minutes). Sedimented particles, presumably virus particles, contained the common sarcoma-leucosis antigen as well.