Antibodies against a preselected peptide recognize and neutralize foot and mouth disease virus.

A major antibody combining site on foot and mouth disease virus (FMDV) serotype O1K has been identified in a predicted surface helix of viral protein 1 (VP1) between amino acid residues 144 and 159. A hexadecapeptide covering this sequence elicits high titers of antibodies that specifically recognize and neutralize FMDV. The high quality of the immune response is attributed to a particularly stable conformation of the antigenic amino acid sequence, which is most likely an alpha-helix.

A non-virion surface antigen on Moloney sarcoma virus-transformed non-producer and producer cells.

Sera from STU mice bearing sarcomas induced by cells producing the Moloney sarcoma-helper-virus (M-MSV/MLV) complex were cytotoxic for these cells as well as for M-MSV non-producer and M-MLV producer cells. Analysis by polyacrylamide gel electrophoresis of 125I-labelled surface antigens immunoprecipitated with such sera revealed the virus envelope glycoprotein gp71 on the producer cells and an additional antigen of mol. wt 55 K on the M-MSV-transformed producer and non-producer cells.

Tumors induced by progressor sarcoma virus (Moloney) in mice: growth in the presence of an immune response and isolation of autonomously growing cells.

Courses of tumors, which had been induced in adult STU mice with a regressor and with a progressor strain of Moloney sarcoma virus (MSV-M) were followed and compared. All 73 tumors induced by the regressor strain of MSV-M (R-MSV-M) regressed and 181 of 183 tumors induced by a progressor strain (P-MSV-M) grew progressively and killed their hosts between 16 and 171 days after infection. Even after inoculation of about 4 FFU of P-MSV-M tumor development may occur and lead to progressively growing tumors.

Growth pattern of tumours in mice induced by murine Moloney sarcoma-virus and sarcoma-virus-transformed cells.

Transplantation of a Moloney sarcoma-virus (MSV-M)-transformed producer cell line (Sac(+)) induced progressively or regressively growing tumours in mice. Progressive growth always occurred after transplantation of an MSV-M non-producer transformant (Sac(-)), whereas the MSV-M released from the producer cells (Sac virus) always induced tumours which regressed. In contrast to the non-producer, the producer transformant Sac(+) as well as Sac virus induced a strong immune response, detected in vitro by cell- and antibody-mediated cytotoxicity assays, and in vivo by transplantation immunity.

Nonproducer malignant tumor cells with rescuable sarcoma virus genome isolated from a recurrent Moloney sarcoma.

Cells from a secondary tumor developing at the site of a regressed Moloney sarcoma virus-induced tumor could be passaged in adult STU mice by intramuscular and intraperitoneal inoculation. The tumors induced by these cells, as well as by a cell line derived from it, grew progressively and led to death of the animals between 3 and 7 wk after tumor transplantation. No evidence for production of virus from these cells was obtained or for the presence of viral antigens (p30, gp69/71).

Togaviridae.

The family Togaviridae is described; it contains four genera--Alphavirus, Flavivirus, Pestivirus and Rubivirus--and additional members. The main characteristics of the family are as follows: single-stranded, linear RNA, molecular weight about 4 X 10(6). Virions have isometric nucleocapsids surrounded by a lipoprotein envelope containing host cell lipid and virus-specified polypeptides including one or more glycopeptides.

Purification of a glycoprotein from bovine leukemia virus (BLV).

A precipitating antigen of bovine leukemia virus was isolated by isoelectric focusing and Sephadex gel filtration. In SDS-polyacrylamide gel electrophoresis it was found to be a homogeneous protein with a relative molecular weight of 69000 daltons. Because of its relative molecular weight and staining characteristics it was designated as BLV gp69.

Detection of cytotoxic lymphoid spleen cells from STU-mice with Moloney sarcoma by a 3H-proline microcytotoxicity assay.

A microcytoxicity assay with 3H-proline prelabeled target cells was used for the detection of sensitized lymphoid spleen cells from STU inbred mice inoculated with Moloney sarcoma virus (MSV-M) or ascitic MSV-M tumor cells. The target cell line was derived from ascitic MSV-M tumor cells. With regard to the specificity of the assay nonimmune slpeen cells displayed no or only a weak cytotoxicity against these cells, and this was also the case when 3H-proline-labeled secondary cultures of syngeneic mouse embryo cells were exposed to both sensitized and nonimmune spleen cells.

Tumor inhibiting capacity of spleen and lymph node cells from mice with murine sarcoma virus (MSV-M)-induced tumors.

The direct tumor inhibiting capacity of spleen and lymph node cells obtained from mice in different stages of Moloney sarcoma virus (MSV-M)-induced tumor development was studied. MSV-M producing ascitic tumor cells with a tumor dosis50 of about 10(3) cells and a mean latent period--depending on the amount of transplanted cells--of6-12 days were used as target cells. They were mixed with dilutions of spleen and lymph node cells obtained from mice at various times after infection with MSV-M.

Bunyaviruses and Bunyaviridae.

A new family is described, the Bunyaviridae, which contains a single genus, Bunyavirus. The main characteristics of the family are as follows: single-stranded RNA, total molecular weight about 7 X 10(6) daltons, probably in three segments. Virions spherical, enveloped particles 90-100 nm in diameter.