HIV-1-specific B cell activation. A major constituent of spontaneous B cell activation during HIV-1 infection.
B cell activation is a well known consequence of HIV-1 infection, and seropositive subjects show high numbers of spontaneously activated Ig-secreting cells in circulation. To better define the importance of the HIV-1-specific response in this phenomenon, we first studied whether in vitro spontaneous anti-HIV-1 antibody production was accompanied by reactivation of memory B lymphocytes. Unstimulated PBL from HIV-1-infected individuals with prior history of hepatitis B and/or EBV infection did not consistently show spontaneous in vitro synthesis of anti-hepatitis B core Ag or anti-EBV antibodies; in addition, PWM-induced synthesis of anti-hepatitis B virus and anti-EBV antibodies was decreased compared to HIV-1-seronegative subjects. Moreover, in comparing the frequencies of activated HIV-1-specific B cell precursors and activated Ig-secreting precursors in limiting dilution experiments, a sizable fraction (20 to 40%) of circulating cells spontaneously secreting Ig produced antibody against HIV-1 determinants. The ratio between the two frequencies fitted in very well with the amount of Ig removed from unstimulated culture supernatants after HIV-1-specific antibody absorption with solid-phase HIV-1. These findings indicate that B cell activation during HIV-1 infection is mainly oriented toward a specific response to HIV-1 determinants; the possible relevance of this phenomenon to lymphomagenesis in AIDS patients is discussed.
Amadori
A
A
Institute of Oncology, University of Padova, Italy.
Zamarchi
R
R
Ciminale
V
V
Del Mistro
A
A
Siervo
S
S
Alberti
A
A
Colombatti
M
M
Chieco-Bianchi
L
L
D000042:Absorption; D000163:Acquired Immunodeficiency Syndrome / Q000276:immunology*; D000328:Adult; D001402:B-Lymphocytes / Q000276:immunology* / Q000378:metabolism; D002478:Cells, Cultured; D000939:Epitopes / Q000276:immunology*; D005260:Female; D015483:HIV Antibodies / Q000096:biosynthesis; D015488:HIV Antigens / Q000096:biosynthesis / Q000276:immunology*; D015497:HIV-1 / Q000276:immunology*; D006508:Hepatitis Antibodies / Q000096:biosynthesis; D006512:Hepatitis B Core Antigens / Q000276:immunology; D004854:Herpesvirus 4, Human / Q000276:immunology; D006801:Humans; D007958:Leukocyte Count; D008213:Lymphocyte Activation; D008297:Male; D013234:Stem Cells / Q000276:immunology / Q000378:metabolism
D000939:Epitopes; D015483:HIV Antibodies; D015488:HIV Antigens; D006508:Hepatitis Antibodies; D006512:Hepatitis B Core Antigens