Biomaterial Database

HIV infection-associated immune activation occurs by two distinct pathways that differentially affect CD4 and CD8 T cells. 2008

Marta Catalfamo, and Michele Di Mascio, and Zonghui Hu, and Sharat Srinivasula, and Vishakha Thaker, and Joseph Adelsberger, and Adam Rupert, and Michael Baseler, and Yutaka Tagaya, and Gregg Roby, and Catherine Rehm, and Dean Follmann, and H Clifford Lane

Clinical and Molecular Retrovirology Section, Laboratory of Immunoregulation and Biostatistics Research Branch, National Institute of Allergy and Infectious Diseases, National Institutes of Health, Bethesda, MD 20892, USA. catalfam@niaid.nih.gov

HIV infection is characterized by a brisk immune activation that plays an important role in the CD4 depletion and immune dysfunction of patients with AIDS. The mechanism underlying this activation is poorly understood. In the current study, we tested the hypothesis that this activation is the net product of two distinct pathways: the inflammatory response to HIV infection and the homeostatic response to CD4 T cell depletion. Using ex vivo BrdU incorporation of PBMCs from 284 patients with different stages of HIV infection, we found that CD4 proliferation was better predicted by the combination of CD4 depletion and HIV viral load (R(2) = 0.375, P < 0.001) than by either parameter alone (CD4 T cell counts, R(2) = 0.202, P < 0.001; HIV viremia, R(2) = 0.302, P < 0.001). Interestingly, CD8 T cell proliferation could be predicted by HIV RNA levels alone (R(2) = 0.334, P < 0.001) and this predictive value increased only slightly (R(2) = 0.346, P < 0.001) when CD4 T cell depletion was taken into account. Consistent with the hypothesis that CD4 T cell proliferation is driven by IL-7 as a homeostatic response to CD4 T cell depletion, levels of phosphorylated STAT-5 were found to be elevated in naive subsets of CD4 and CD8 T cells from patients with HIV infection and in the central memory subset of CD4 T cells. Taken together these data demonstrate that at least two different pathways lead to immune activation of T cells in patients with HIV infection and these pathways differentially influence CD4 and CD8 T cell subsets.

UI	MeSH Term	Description	Entries
D008212	Lymphocyte Depletion	Immunosuppression by reduction of circulating lymphocytes or by T-cell depletion of bone marrow. The former may be accomplished in vivo by thoracic duct drainage or administration of antilymphocyte serum. The latter is performed ex vivo on bone marrow before its transplantation.	Depletion, Lymphocyte
D008213	Lymphocyte Activation	Morphologic alteration of small B LYMPHOCYTES or T LYMPHOCYTES in culture into large blast-like cells able to synthesize DNA and RNA and to divide mitotically. It is induced by INTERLEUKINS; MITOGENS such as PHYTOHEMAGGLUTININS, and by specific ANTIGENS. It may also occur in vivo as in GRAFT REJECTION.	Blast Transformation,Blastogenesis,Lymphoblast Transformation,Lymphocyte Stimulation,Lymphocyte Transformation,Transformation, Blast,Transformation, Lymphoblast,Transformation, Lymphocyte,Activation, Lymphocyte,Stimulation, Lymphocyte
D010766	Phosphorylation	The introduction of a phosphoryl group into a compound through the formation of an ester bond between the compound and a phosphorus moiety.	Phosphorylations
D006801	Humans	Members of the species Homo sapiens.	Homo sapiens,Man (Taxonomy),Human,Man, Modern,Modern Man
D015331	Cohort Studies	Studies in which subsets of a defined population are identified. These groups may or may not be exposed to factors hypothesized to influence the probability of the occurrence of a particular disease or other outcome. Cohorts are defined populations which, as a whole, are followed in an attempt to determine distinguishing subgroup characteristics.	Birth Cohort Studies,Birth Cohort Study,Closed Cohort Studies,Cohort Analysis,Concurrent Studies,Historical Cohort Studies,Incidence Studies,Analysis, Cohort,Cohort Studies, Closed,Cohort Studies, Historical,Studies, Closed Cohort,Studies, Concurrent,Studies, Historical Cohort,Analyses, Cohort,Closed Cohort Study,Cohort Analyses,Cohort Studies, Birth,Cohort Study,Cohort Study, Birth,Cohort Study, Closed,Cohort Study, Historical,Concurrent Study,Historical Cohort Study,Incidence Study,Studies, Birth Cohort,Studies, Cohort,Studies, Incidence,Study, Birth Cohort,Study, Closed Cohort,Study, Cohort,Study, Concurrent,Study, Historical Cohort,Study, Incidence
D015496	CD4-Positive T-Lymphocytes	A critical subpopulation of T-lymphocytes involved in the induction of most immunological functions. The HIV virus has selective tropism for the T4 cell which expresses the CD4 phenotypic marker, a receptor for HIV. In fact, the key element in the profound immunosuppression seen in HIV infection is the depletion of this subset of T-lymphocytes.	T4 Cells,T4 Lymphocytes,CD4-Positive Lymphocytes,CD4 Positive T Lymphocytes,CD4-Positive Lymphocyte,CD4-Positive T-Lymphocyte,Lymphocyte, CD4-Positive,Lymphocytes, CD4-Positive,T-Lymphocyte, CD4-Positive,T-Lymphocytes, CD4-Positive,T4 Cell,T4 Lymphocyte
D015658	HIV Infections	Includes the spectrum of human immunodeficiency virus infections that range from asymptomatic seropositivity, thru AIDS-related complex (ARC), to acquired immunodeficiency syndrome (AIDS).	HTLV-III Infections,HTLV-III-LAV Infections,T-Lymphotropic Virus Type III Infections, Human,HIV Coinfection,Coinfection, HIV,Coinfections, HIV,HIV Coinfections,HIV Infection,HTLV III Infections,HTLV III LAV Infections,HTLV-III Infection,HTLV-III-LAV Infection,Infection, HIV,Infection, HTLV-III,Infection, HTLV-III-LAV,Infections, HIV,Infections, HTLV-III,Infections, HTLV-III-LAV,T Lymphotropic Virus Type III Infections, Human
D016207	Cytokines	Non-antibody proteins secreted by inflammatory leukocytes and some non-leukocytic cells, that act as intercellular mediators. They differ from classical hormones in that they are produced by a number of tissue or cell types rather than by specialized glands. They generally act locally in a paracrine or autocrine rather than endocrine manner.	Cytokine
D016516	CD4-CD8 Ratio	Ratio of T-LYMPHOCYTES that express the CD4 ANTIGEN to those that express the CD8 ANTIGEN. This value is commonly assessed in the diagnosis and staging of diseases affecting the IMMUNE SYSTEM including HIV INFECTIONS.	T4-T8 Ratio,CD4 CD8 Ratio,CD4-CD8 Ratios,T4 T8 Ratio,T4-T8 Ratios
D049109	Cell Proliferation	All of the processes involved in increasing CELL NUMBER including CELL DIVISION.	Cell Growth in Number,Cellular Proliferation,Cell Multiplication,Cell Number Growth,Growth, Cell Number,Multiplication, Cell,Number Growth, Cell,Proliferation, Cell,Proliferation, Cellular