Cytotoxic T lymphocytes (CTL) can control some viral infections and may be important in the control of lentiviruses, including human immunodeficiency virus type 1. Since there is limited evidence for an in vivo role of CTL in control of lentiviruses, dissection of immune mechanisms in animal lentiviral infections may provide needed information. Horses infected with equine infectious anemia virus (EIAV), a lentivirus, have acute plasma viremia which is terminated in immunocompetent horses. Viremic episodes may recur, but most horses ultimately control infection and become asymptomatic carriers. To begin dissection of the immune mechanisms involved in EIAV control, peripheral blood mononuclear cells (PBMC) from infected horses were evaluated for CTL to EIAV-infected cells. By using noninfected and EIAV-infected autologous equine kidney (EK) cells in

Rapid and accurate detection of Anaplasma marginale-infected cattle would enhance anaplasmosis control procedures and evaluation of vaccines. Current tests based on detection of antibodies in serum are not widely used for several reasons, including the occurrence of either false-positive or false-negative results. We evaluated binding of antibodies in serum to a subunit antigen isolated from A. marginale initial bodies-major surface protein 3 (MSP-3). MSP-3 was detected in lysates of eight geographically different isolates of A. marginale and purified by affinity chromatography with monoclonal antibody AmG75C2. Antibodies from cattle infected with any of five geographically different isolates of A. marginale reacted in immunoblots with MSP-3. Sera from uninfected cattle and cattle infected with another rickettsial organism and two hemoprotozoal organisms failed to react with MSP-3. Six carrier cattle infected with the Florida isolate of A. marginale had antibody titers to MSP-3 ranging from i03 to 106 during a 5-year evaluation period. Since specific antibodies to isolated MSP-3 persist in high titers in long-term carrier cattle sera and MSP-3 is common among A. marginale isolates, it is recommended as a subunit antigen for an anaplasmosis test.

To dissect mechanisms of caprine arthritis-encephalitis lentivirus-induced arthritis, an undefined immunodominant viral glycoprotein, gp9O (G. C. Johnson, A. F. Barbet, P. Klevjer-Anderson, and T. C. McGuire, Infect. Immun. 41:657-665, 1983), was characterized. Monoclonal antibody to gp9O and specific antiserum to env gene products demonstrated that gp9O was a transmembrane protein (TM) dimer. Goats with progressive arthritis had high antibody titers to oligomeric and monomeric (38-kDa) TM.

A recombinant infectious hematopoietic necrosis virus (IHNV) glycoprotein (G protein) was produced in insect cells using a baculovirus vector (Autographa californica nuclear polyhedrosis virus). Characteristics of this protein were evaluated in relation to native viral G protein. A full-length (1.6 kb) cDNA copy of the glycoprotein gene of IHNV was inserted into the baculovirus vector under control of the polyhedrin promoter. High levels of G protein (approximately 0.5 pg/l X 10' cells) were produced in Spodoptera frugiperda (Sf9) cells following recombinant baculovirus infection. Analysis of cell lysates by sodium dodecyl sulfate polyacrylamide gel electrophoresis (SDS-PAGE) and Western blot revealed a recombinant IHNV G of slightly higher mobihty on the gel than the viral G protein. Differences in mobhty were abrogated by endoglycosidase treatment. When the recombinant G protein was produced in insect cells at 20°C (RecG,,,), inmiunostaining and cell fusion activity demonstrated surface localization of the protein. In contrast, when recombinant protein was produced at 27°C (RecG,,,,), G protein was sequestered within the cell, suggesting that at the 2 different temperatures processing differences may exist. Eleven monoclonal antibodies (MAbs) were tested by irnmunoblotting for reactivity to the recombinant G protein. All 11 MAbs reacted to the reduced proteins. Four MAbs recognized both Re&,,,, and RecG,,, under non-reducing conditions; however, 1 neutralizing MAb (92A) recognized RecG,,, but failed to react to RecChigh under non-reducing conditions. This suggests that differences exist between RecG,,, and RecGhrgh which may have implications in the development of a properly folded recombinant G protein with the abihty to elicit protective immunity in fish.

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