Cross-reactivity between caprine arthritis-encephalitis virus and type 1 human immunodeficiency virus.
BACKGROUND
Caprine arthritis encephalitis (CAE) is caused by the lentivirus caprine arthritis-encephalitis virus (CAEV), a member of the Retroviridae family that also includes the human immunodeficiency virus (HIV). Serum of CAEV-infected goats cross-reacts with HIV-1 antigens in enzyme-linked immunosorbent assay (ELISA) tests. We attempted to identify the proteins responsible for this cross-reactivity.


METHODS
Fifty selected human sera (30 positive, 10 negative, and 10 indeterminate to HIV-1 by Western blot) and 50 selected goat sera (33 positive and 17 negative to CAEV by ELISA) were evaluated. Human and goat sera were tested by Western blot against HIV-1 and CAEV antigens.


RESULTS
Cross-reactivity between surface glycoproteins gp120 (HIV-1) and gp135 (CAEV) was specific. Positive reaction of human sera to CAEV gp135 was more intense than that of goat sera to HIV-1 gp120. Surface glycoprotein sequences of the two viruses were compared by Lasergene software (Dynex Technologies, Inc., Chantilly, VA, USA). Three homologous regions were identified: the first in the internal domain of gp120; the second in the beta3 loop, and still another-with the greatest homology-in a short sequence of the proximal region of the external domain of gp120 between loops beta4 and beta8.


CONCLUSIONS
Surface glycoproteins of HIV-1 and CAEV share structural regions essential for viral adsorption and for induction of neutralizing antibodies. Thus, human contact with CAEV eventually could be a possible source of HIV-1 false positive reactions and must be considered in the interpretation of HIV serologic results.
Tesoro-Cruz
Emiliano
E
Unidad de Investigación Médica en Inmunología, Centro Médico Nacional Siglo XXI, Instituto Mexicano del Seguro Social, Mexico City, DF, Mexico.
Hernández-González
Rafael
R
Kretschmer-Schmid
Roberto
R
Aguilar-Setién
Alvaro
A
D000595:Amino Acid Sequence; D000818:Animals; D000956:Antigens, Viral / Q000737:chemistry / Q000276:immunology*; D016088:Arthritis-Encephalitis Virus, Caprine / Q000235:genetics / Q000276:immunology* / Q000378:metabolism; D002478:Cells, Cultured; D003429:Cross Reactions; D004797:Enzyme-Linked Immunosorbent Assay; D006041:Goats; D015497:HIV-1 / Q000235:genetics / Q000276:immunology* / Q000378:metabolism; D006801:Humans; D008969:Molecular Sequence Data; D016415:Sequence Alignment; D014764:Viral Proteins / Q000737:chemistry / Q000235:genetics / Q000276:immunology* / Q000378:metabolism
D000956:Antigens, Viral; D014764:Viral Proteins