Function and phenotype of immature CD4+ lymphocytes in healthy infants and early lymphocyte activation in uninfected infants of human immunodeficiency virus-infected mothers.
The function and phenotypes of CD4+ lymphocytes in infants are different than in adults and are modulated by maturational changes and exposure to environmental antigens. Infants of non-human immunodeficiency virus (HIV)-infected mothers and uninfected infants of HIV-infected mothers, 0 to 6 months of age, were examined for CD4+ lymphocyte function by in vitro interleukin-2 (IL-2) production and for CD4+ phenotypes by three-color flow cytometry. A minority of these uninfected infants (28%) had functional responses similar to those of healthy adult women (IL-2 production in response to anti-CD3, alloantigen, and mitogen), while the remainder were capable of responding to alloantigen and mitogen but not to anti-CD3. We did demonstrate reduced phytohemagglutinin-stimulated IL-2 production in uninfected infants born to HIV-seropositive mothers compared to that in infants from seronegative mothers. The proportions of CD3+ CD4+, CD4+ HLA-DR- CD38+, and CD4+ CD45RA+ RO- (naive) lymphocytes were much higher in infants than in adults, and the proportions of CD4+ CD45RA- RO+ (memory) and CD4+ CD25+ (IL-2 receptor-bearing) lymphocytes were lower in infants than in adults. The proportions of activated (CD4+ HLA-DR+ CD38+) and memory (CD4+ CD45RA- RO+) lymphocytes were increased in uninfected infants of HIV-infected mothers compared to infants of uninfected mothers. Therefore, T-helper-cell function is immature in many infants, but the CD4+ lymphocytes of some HIV-exposed, uninfected infants have been stimulated by antigen at an early age.
Rich
K C
KC
Department of Pediatrics, University of Illinois at Chicago, USA.
Siegel
J N
JN
Jennings
C
C
Rydman
R J
RJ
Landay
A L
AL
D000328:Adult; D000945:Antigens, Differentiation, T-Lymphocyte / Q000378:metabolism; D015496:CD4-Positive T-Lymphocytes / Q000145:classification / Q000166:cytology / Q000276:immunology*; D002454:Cell Differentiation; D005260:Female; D015658:HIV Infections / Q000150:complications* / Q000276:immunology*; D018023:HIV Seronegativity / Q000276:immunology; D006679:HIV Seropositivity / Q000150:complications / Q000276:immunology; D006801:Humans; D066298:In Vitro Techniques; D007223:Infant; D007231:Infant, Newborn; D007376:Interleukin-2 / Q000096:biosynthesis; D008213:Lymphocyte Activation; D008431:Maternal-Fetal Exchange / Q000276:immunology; D010641:Phenotype; D010835:Phytohemagglutinins / Q000494:pharmacology; D011247:Pregnancy; D011251:Pregnancy Complications, Infectious / Q000276:immunology*
D000945:Antigens, Differentiation, T-Lymphocyte; D007376:Interleukin-2; D010835:Phytohemagglutinins