Monoclonal antibodies to a tumour-associated antigen isolated from circulating immune complexes of bovine leukemia virus-infected cattle.

From circulating immune complexes (ICs) of BLV-infected cattle, an antigen preparation was produced that contained some virus-specific proteins and a tumour-associated antigen. Eleven hybridoma clones were produced that secreted monoclonal antibodies (MoAbs) to this tumour-associated antigen, and two of them, MoAbs 1B4 and 1E9, were used in further studies. Most antibodies were of IgG1 subclass and showed no cytotoxic activity towards lymphocytes of BLV-positive cattle or to certain tumour cells.

Two tumor-associated membrane antigens defined by monoclonal antibodies in a transplantable sarcoma induced by Rous sarcoma virus in rat.

Two hybridoma clones have been produced by hybridization of murine myeloma cell line PAI and splenocytes from BALB/c mice immunized with cells from a transplantable sarcoma induced in rat by SR-RSV. The antibody produced by hybridoma clone 2C2 was of subclass IgG3 and recognized a cell surface antigen of 52 kD. It only cross-reacted with cells from SR-RSV-induced sarcoma in hamster, but not with cells from the chicken RSV-induced sarcoma, nor with a number of methylcholanthrene sarcomas and various other tumors of viral or other etiology developed in rats, mouse, hamsters or chickens.

Pathogenicity of avian myelocytomatosis virus MC29 in two lines of chickens.

The pathogenicity of avian myelocytomatosis virus MC29 was studied in F1 hybrids of two Prague inbred lines of chickens-CC xIA (B4/B7 genotype) and CB x IA (B12/B7 genotype). A shorter latent period and a higher mortality was found in the CC x IA chickens. In most chickens of this group, subperiosteal accumulations of primitive cells on the ribs, sternum and pelvic bones were observed, which were never detected in the CB x IA chickens.

Protein A in the stable L-forms of Staphylococcus aureus.

The presence of protein A in the stable L-form of S. aureus BM 3041 was proved. Its amino acid composition and electrophoretic characteristics were compared with the parent strain.