J Virol. 2005 May;79(10):6377-91.

The Nef-mediated AIDS-like disease of CD4C/human immunodeficiency virus transgenic mice is associated with increased Fas/FasL expression on T cells and T-cell death but is not prevented in Fas-, FasL-, tumor necrosis factor receptor 1-, or interleukin-1beta-converting enzyme-deficient or Bcl2-expressing transgenic mice.

Priceputu E, Rodrigue I, Chrobak P, Poudrier J, Mak TW, Hanna Z, Hu C, Kay DG, Jolicoeur P.

Source

Clinical Research Institute of Montreal, 110 Pine Avenue West, Montreal, Quebec H2W 1R7, Canada. Paul.Jolicoeur@ircm.qc.ca.

Abstract

CD4(+)- and CD8(+)-T-cell death is a frequent immunological dysfunction associated with the development of human AIDS. We studied a murine model of AIDS, the CD4C/HIV transgenic (Tg) mouse model, to assess the importance of the apoptotic pathway in human immunodeficiency virus type 1 (HIV-1) pathogenesis. In these Tg mice, Nef is the major determinant of the disease and is expressed in immature and mature CD4(+) T cells and in cells of the macrophage/myeloid lineage. We report here a novel AIDS-like phenotype: enhanced death, most likely by apoptosis (as assessed by 7-aminoactinomycin D and annexin V/propidium iodide staining), of Tg thymic and peripheral CD4(+) and CD8(+) T cells. The Tg CD4(+) and CD8(+) T cells were also more susceptible to cell death after activation in vitro in mixed lymph node (LN) cultures. However, activation-induced cell death was not higher in Tg than in non-Tg-purified CD4(+) T cells. In addition, expression of Fas and FasL, assessed by flow cytometry, was increased in CD4(+) and CD8(+) T cells from Tg mice compared to that of non-Tg littermates. Despite the enhanced expression of Fas and FasL on Tg CD4(+) and CD8(+) T cells, Fas (lpr/lpr) and FasL (gld/gld) mutant CD4C/HIV Tg mice developed an AIDS-like disease indistinguishable from lpr/+ and gld/+ CD4C/HIV Tg mice, including loss of CD4(+) T cells. Similarly, CD4C/HIV Tg mice homozygous for mutations of two other genes implicated in cell death (interleukin-1beta-converting enzyme [ICE], tumor necrosis factor receptor 1 [TNFR-1]) developed similar AIDS-like disease as their respective heterozygous controls. Moreover, the double-Tg mice from a cross between the Bcl2/Wehi25 and CD4C/HIV Tg mice showed no major protection against disease. These results represent genetic evidence for the dispensable role of Fas, FasL, ICE, and TNFR-1 on the development of both T-cell loss and organ disease of these Tg mice. They also provide compelling evidence on the lack of protection by Bcl2 against Tg CD4(+)-T-cell death. In view of the high resemblance between numerous phenotypes observed in the CD4C/HIV Tg mice and in human AIDS, our findings are likely to be relevant for the human disease.

PMID:: 15858021; [PubMed - indexed for MEDLINE]
PMCID:: PMC1091671

Free PMC Article

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FIG. 5.

CD4C/HIV Tg mice deficient for Fas develop an AIDS like disease. (A) Survival curve of homozygous lpr/lpr (n = 21) or heterozygous lpr/+ (n = 20) CD4C/HIV Tg mice as well as lpr/lpr (n = 6) and lpr/+ (n = 9) non-Tg mice. Mice were observed for up to 8 months. (B) Kidney histology of non-Tg and lpr/lpr or lpr/+ Tg mice. Note comparable changes (cystic dilatations, interstitial nephritis, and segmental glomerulosclerosis) in 3- to 6-month-old lpr/lpr and lpr/+ Tg mice. (C) pLN size and weight. pLN hypertrophy observed in lpr/lpr non-Tg mice is much reduced in lpr/lpr Tg mice. (D) FACS profiles of CD4⁺/TCRαβ⁺ and DN B220⁺ TCRαβ⁺ T cells from 7-week-old control and lpr/lpr Tg mice. pLN cells were stained, and FACS analysis was performed as described in the legend to Fig. 4C. For B220⁺ TCRαβ⁺ DN cells, gating was first done on TCRαβ⁺ cells. The dot plot represents one representative experiment out of eight. (E) Detection of Nef expression in purified (sorted) DN B220⁺ TCRαβ⁺ cells by ISH. pLN Tg cells were stained with anti-CD4/CD8/TCRαβ/B220 MAbs, and the DN B220⁺ TCRαβ⁺ cells were purified by cell sorting. About 10⁵ cells prepared by cytospotting were processed for ISH as described in Materials and Methods and hybridized with an antisense or control sense ³⁵S-labeled HIV-1-specific riboprobe. Panels a and b are non-Tg negative control cells, panels c and d are Tg thymocytes (positive controls, wild type [WT]), and panels e and f are DN B220⁺ TCRαβ⁺ sorted cells (DN). Magnification, ×250. For quantitation (g), 1,410 cells (in 46 different fields) and 1,054 cells (in 53 fields) were examined after hybridization with the antisense and sense probes, respectively. The experiment was repeated three times with comparable results.

The Nef-Mediated AIDS-Like Disease of CD4C/Human Immunodeficiency Virus Transgenic Mice Is Associated with Increased Fas/FasL Expression on T Cells and T-Cell Death but Is Not Prevented in Fas-, FasL-, Tumor Necrosis Factor Receptor 1-, or Interleukin-1β-Converting Enzyme-Deficient or Bcl2-Expressing Transgenic Mice

J Virol. J Virol;79(10):6377-6391.

FIG. 7.

CD4C/HIV Tg mice overexpressing Bcl2 in T cells are not protected from loss of CD4⁺ T cells. (A) Survival curve of single-CD4C/HIV (n = 10) or double- (CD4C/HIV X Bcl2/Wehi25) (n = 12) Tg mice and their non-Tg (n = 10) or single-Bcl2/Wehi25 Tg (n = 14) controls. Mice were observed for up to 8 months. (B) Kidney histology of non-Tg and single- or double- (CD4C/HIV X Bcl2/Wehi25) Tg mice. Note the comparable changes (cystic dilatations, interstitial nephritis, and segmental glomerulosclerosis) in single-CD4C/HIV and double- (CD4C/HIV X Bcl2/Wehi25) Tg mice. (C) FACS profiles of CD4⁺ T cells from single-CD4C/HIV and double- (CD4C/HIV X Bcl2/Wehi25) Tg mice and their non-Tg controls. pLN cells were stained, and FACS analysis was performed as described in the legend to Fig. 4C. The dot plot represents one representative experiment out of six. (D) Quantitation of CD4⁺ and CD8⁺ T cells in pLN of single- or double- (CD4C/HIV X Bcl2/Wehi25) Tg mice. Data from FACS analysis as shown in panel C were pooled for CD4⁺ and CD8⁺ T cells from 7- to 9-month-old non-Tg (n = 7), single-Bcl2/Wehi25 (n = 7), CD4C/HIV (n = 6), and double- (CD4C/HIV X Bcl2/Wehi25 [n = 7]) Tg mice. Statistical analysis was performed with Student's t test. *, P = 0.04; ***, P < 0.0001. (E) Quantitation of apoptosis/death of CD4⁺ T cells in single-CD4C/HIV or double- (CD4C/HIV X Bcl2/Wehi25) Tg mice. pLN cells, from the same mice presented in panel D were stained with anti-CD4 and 7AAD and analyzed with FACS to obtain apoptosis/death profiles. The percentages of apoptotic/dead CD4⁺ T cells are indicated. The figure represents pooled data from six experiments. Statistical analysis was performed with Student's t test. ***, P < 0.0001. (F) Quantitation of thymocytes in single- or double- (CD4C/HIV X Bcl2/Wehi25) Tg mice. Data were obtained from 6- to 10-week-old non-Tg (n = 6), single-Bcl2/Wehi25 (n = 6), CD4C/HIV (n = 6), and double- (CD4C/HIV X Bcl2/Wehi25) (n = 6) Tg mice. Statistical analysis was performed with Student's t test. *, P = 0.05; **, P < 0.001; ***, P < 0.0001.

J Virol. J Virol;79(10):6377-6391.