A technique originally described for the isolation of Friend leukaemia virus envelope polypeptides  yields equivalent structures from Moloney leukaemia, AKR and BALB/c xenotropic virus as well as feline leukaemia virus. The envelope polypeptides are obtained as micellar protein complexes, named rosettes. Rosettes of the five m am malian type-C viruses examined are indistinguishable by electron microscopy. Separation of these aggregates in polyacrylamide gel electrophoresis under nonreducing conditions reveals a glycoprotein of about 85 000 d as their major component. Tryptic peptide analyses identify the viral origin of these polypeptides and emphasize strain specific differences in their primary structure
A glycoprotein of an apparent molecular mass of 46000, gp 46, was enriched by affinity chromatography from the virus-and cell-free culture medium of adult T-cell leukemia virus (ATLV) infected cells, gp 46 was specifically precipitated with sera from patients with adult T-cell leukemia known to react with the adult T-cell leukemia associated antigen (ATLA). Thus, gp 46 is a novel component of the ATLA antigen complex.
In C-type particles of mammalian origin, two different antigenic determinants of the interspecies type have been revealed by a comparative study of murine-, feline-, suidian-, simian (woolly monkey) (SSV-1)-and RD114-viruses. With respect to the distribution of interspecies determinants, these viruses can be arranged into two distinct groups; one comprises the rodent- and cat-, the other the pig- and monkey-viruses. RD114-virus appears to share a certain non-interspecies antigenic component with cat viruses (strains Rickard and Gardner) but behaves, as far as its interspecies antigenic determinant is concerned, more similar to pig- and woolly monkey-viruses. In showing the serological differences mentioned, IgG antibody could replace whole serum.
The value of urinary neopterin as a predictive marker for disease progression in SIV- and HIV-2-infected rhesus (Macaca mulatta) and cynomolgus macaques (Macaca fascicularis) was assessed by comparing pre- with postinfection data. Before infection stable baselines for neopterin were observed in both species with significantly higher concentrations in cynomolgus macaques than in rhesus macaques. After infection of cynomolgus macaques with human immunodeficiency virus type 2 (HIV-2) neopterin concentrations exceeded 1.2 - 4.2 times preinfection values, whereas rhesus monkeys infected with simian immunodeficiency virus (SIV) yielded concentrations of more than 8 times above baseline. Increased neopterin concentrations always preceded seroconversion. No rise of neopterin was observed in cynomolgus macaques remaining seronegative after inoculation with HIV-2, whereas after inoculation with SIV neopterin was slightly elevated in rhesus monkeys despite remaining seronegative. In animals with high virus replication a pronounced increase of neopterin levels was followed by signs of immunodeficiency. Therefore like in HIV-1-infected man, in macaques infected with SIV or HIV-2 the urinary neopterin concentration is an early and reliably predictive marker for AIDS disease progression and reflects pathogenicity. This parameter can be easily assessed in study protocols for drug and vaccine tests in monkeys as in man.