Amino Acid Sequence ; Blood Donors ; Gene Deletion ; Gene Products, nef ; chemistry ; genetics ; Humans ; Molecular Sequence Data ; nef Gene Products, Human Immunodeficiency Virus

BACKGROUNDThe correlation between HIV-1 Nef-specific CD8 T-cell responses and markers of HIV-1 disease progression still remains unclear. This study analysed and compared the role of HIV-1 Nef-specific CD8 T-cell responses in patients with different disease status.

METHODSTwo groups of patients with HIV-1 subtype B infection were selected according to CD4 count and clinical manifestations: long-term nonprogressors (LTNPs, n = 20) and advanced progressors (APs, CD4 count < 500 cells/microl, n = 34). Nef-specific CD8 T-cell responses were studied by interferon-gamma ELISpot assay against 3 pools of HIV-Nef peptides.

RESULTSNef-specific CD8 T-cell responses did not correlate with viral load or CD4 count in all patients and no significant differences were found in the magnitude of Nef-specific CD8 T-cell responses between groups LTNPs and APs (670 SFC/10(6) peripheral blood mononuclear cells vs 1107 SFC/10(6) peripheral blood mononuclear cells, P = 0.255). Further comparisons showed that there were also no significant correlations observed in group LTNPs, but Nef-specific CD8 T cells correlated negatively with viral load (r = -0.397, P = 0.020) and positively with CD4 count (r = 0.364, P = 0.034) in group APs.

CONCLUSIONThese data suggest that different correlation patterns between Nef-specific CD8 T-cell responses and disease progression exist in LTNPs and APs. Although a negative association was observed with concurrent plasma HIV RNA in APs, Nef-specific CD8 T-cell responses might fail to play a protective role in different stages of HIV-1 infection.

Acquired Immunodeficiency Syndrome ; immunology ; Adult ; CD4 Lymphocyte Count ; CD8-Positive T-Lymphocytes ; immunology ; Disease Progression ; Female ; Gene Products, nef ; immunology ; HIV-1 ; classification ; Humans ; Male ; Middle Aged ; RNA, Viral ; blood ; nef Gene Products, Human Immunodeficiency Virus

OBJECTIVETo review the recent developments in and research into binding receptors of hepatitis C virus (HCV) and especially the role of dendritic cell-specific adhesion receptor (DC-SIGN) in HCV.

DATA SOURCESBoth Chinese- and English-language literature was searched using MEDLINE (2000 - 2003) and the databank of Chinese-language literature (2000 - 2003).

STUDY SELECTIONRelevant articles on DC-SIGN and HCV binding receptors in recent domestic and foreign literature were selected.

DATA EXTRACTIONData were mainly extracted from 40 articles which are listed in the references section of this review.

RESULTSDC-SIGN, a dendritic cell-specific adhesion receptor and a type II transmembrane mannose-binding C-type lectin, is very important in the function of dendritic cells (DC), both in mediating naïve T cell interactions through ICAM-3 and as a rolling receptor that mediates the DC-specific ICAM-2-dependent migration processes. It can be used by HCV and other viral and bacterial pathogens including human immunodeficiency virus (HIV), Ebola virus, CMV and Mycobacterium tuberculosis to facilitate infection. Both DC-SIGN and DC-SIGNR can act either in cis, by concentrating virus on target cells, or in trans, by transmission of bound virus to a target cell expressing appropriate entry receptors. Recent report showed that DC-SIGN not only plays a role in entry into DC, HCV E2 interaction with DC-SIGN might also be detrimental to the interaction of DC with T cells during antigen presentation.

CONCLUSIONSDC-SIGNs are high-affinity binding receptors for HCV. The clinical strategies that target DC-SIGN may be successful in restricting HCV dissemination and pathogenesis as well as directing the migration of DCs to manipulate appropriate immune responses in autoimmunity and tumorigenic situations.

Animals ; Cell Adhesion Molecules ; physiology ; Gene Products, nef ; physiology ; Hepacivirus ; physiology ; Humans ; Lectins, C-Type ; physiology ; Receptors, CCR5 ; physiology ; Receptors, Cell Surface ; physiology ; Receptors, Virus ; physiology ; Viral Envelope Proteins ; physiology

OBJECTIVETo study the specific amino acid variation in Nef that may be related to disease progression after infection with HIV-1 subtype B, a predominant strain circulating in China, and to determine whether changes in Nef secondary structure may influence different stages of AIDS development based on the concept that the Nef gene of HIV infection dramatically alter the severity of viral infection and virus replication and disease progression, and that long-term non-progressors (LTNP) of HIV infection are commonly associated with either a deletion of the Nef gene or the defective Nef alleles.

METHODSThe study subjects were divided into LTNP1(n=14), LTNP2 (n=16) and slow progressor (SP, n=19) groups for mutational analysis of the Nef sequence. The data were obtained by using Bioedit, MEGA, Anthewin and SAS software.

RESULTSResidues in Nef TA(48/49) and K151 occurred more frequently in the LTNP group while AA(48/49) was more frequently observed in the SP group. Of the differences observed in the secondary structure comparison using Nef consensus sequences of these three groups, one was roughly corresponding to the Nef(48/49) mutation site.

CONCLUSIONTA(48/49), K(151), and AA(48/49) in the Nef gene might be associated with the different stages of HIV infection, and there may be a link between the Nef secondary structure and the progression of HIV-1 infection.

Amino Acid Sequence ; Base Sequence ; Blood Donors ; CD4 Lymphocyte Count ; China ; epidemiology ; Disease Progression ; Gene Products, nef ; genetics ; HIV Infections ; epidemiology ; virology ; HIV Long-Term Survivors ; HIV-1 ; classification ; genetics ; Humans ; Molecular Sequence Data ; Mutation ; genetics ; Time Factors