Evaluation of testing algorithms following the use of combination HIV-1/HIV-2 EIA for screening purposes

Injecting drugs of abuse and immunity: implications for HIV vaccine testing and efficacy

The recreational use of legal and illegal drugs has significant effects on immune responses and can potentially modulate susceptibility to infection by a number of pathogens. A number of agents including cannabinoids (marijuana), cocaine opiates, amphetamines, nicotine and alcohol were demonstrated to have potentially adverse effects on the susceptibility to infections, mediated most likely, by adverse effects on immunity. As such, these drugs of abuse could have significant and potentially adverse effects on the vaccination efficacy of a number of vaccines currently on the market and on potential experimental vaccines currently in the pipeline. This review will present an overview on how drugs of abuse potentially impacts immune responses and vaccination efficacy. The emphasis of this review will be the effects of opiate abuse, as exemplified by injecting/intravenous drug users (IDU), on HIV/AIDS and its potential impact on vaccine efficacy trials against this devastating infection/syndrome.

Two HIV-1 epidemics in Argentina: different genetic subtypes associated with different risk groups

This study determined the risk behaviors and viral subtypes of HIV-1 found in 134 heterosexual HIV-seroprevalent maternity patients, 41 of their sexual partners (men who have sex with women [MSW]), and 95 homosexual men (men who have sex with men [MSM]) from Buenos Aires, Argentina. Peripheral blood mononuclear cells (PBMCs) were purified from blood and used for DNA extraction, amplification, and genotyping by the envelope heteroduplex mobility assay (env HMA). Most of the women had been infected by having sex with an already infected partner (84%), whereas most of the male partners had been infected via drug use (76%). Both the patients and their sexual partners were poorly educated, only 30% having completed secondary school. The MSM study subjects, however, were significantly better educated and had a lower prevalence of injecting drug use.Env HMA subtype F was found in 77% (103 of 134) of the maternity patients, with similar rates in their partners (73%). Most of the remaining samples were env subtype B. All but one of the couples was concordant in subtype. In the MSM risk group, however, only 10% were env HMA subtype F. Ninety percent of the MSM samples were subtype B. There are at least two independent epidemics of HIV-1 infection in Buenos Aires, Argentina. One, in heterosexual men and women, is dominated by env subtype F whereas the other, in homosexual men, is dominated by env subtype B, as determined by env HMA.

An AB recombinant and its parental HIV type 1 strains in the area of the former Soviet Union: low requirements for sequence identity in recombination. UNAIDS Virus Isolation Network

In the former Soviet Union (SU) increasing numbers of HIV-1 infections among injecting drug users (IDU) have been reported, especially in the Ukraine. The main subtype transmitted among the IDUs seems to be subtype A, but limited numbers of subtype B cases have also been reported. In Kaliningrad, Russia, an AB recombinant strain was earlier shown to be responsible for the local outbreak. Here we describe the genetic relationship of HIV-1 strains circulating among IDUs in the former SU. For subtype A and the AB recombinant strains nearly full-length genomes were sequenced, and for one subtype B strain the entire envelope gene was cloned. The relationship between the AB recombinant strain and the subtype A and subtype B strains and the mosaic structure of the recombinant was studied by phylogenetic analysis. Ukrainian A and B strains were shown to be the probable parental viruses of the Kaliningrad AB recombinant strain. In the envelope gene the recombination breakpoint could also be precisely mapped to a region of similarity of only 14 base pairs. This suggests that only short stretches of absolute sequence identity may be needed for efficient RNA recombination between HIV-1 subtypes.

The role of the viral glycoprotein in HIV-1 persistence

The study of the immunological defects which arise from HIV infection has led to a deeper understanding both of the normal immune system and of the mechanisms by which it is damaged in disease. The interactions between viral and host factors during the early stages of HIV infection leads to a post-seroconversion steady state or 'set point' of viral RNA load, which has been shown to be a prognostic marker for subsequent progression rates, further underlining the important role of early immunological responses in the disease process. The changing immune response during the course of infection, together with the changing patterns of antigenicity and tropism leads to a complex series of evolutionary interactions which can be monitored as a series of changes in the properties of the virus over time. Furthermore, significant differences may be seen between the antigenicity of viruses adapted to grow in tissue culture and viruses cultured only briefly in primary cells, and also between the antigenicity of monomeric and oligomeric subunit immunogens. The immunodominant, highly polymorphic and rapidly changing envelope glycoproteins of HIV remains the single biggest target for the design of successful candidate vaccines. The recent crystallisation of one HIV envelope, the proven existence of functionally conserved neutralisation targets and our increasing knowledge of the behaviour of the envelope glycoprotein in vivo offers the possibility that the next generation of vaccine candidates will have a far higher chance of success than has currently been achieved.

Performance characteristics of recombinant enzyme immunoassay to detect antibodies to human immunodeficiency virus type 1 (HIV-1) and HIV-2 and to measure early antibody responses in seroconverting patients

We investigated the performance of a double-antigen sandwich recombinant enzyme immunoassay (EIA; Abbott Laboratories, North Chicago, Ill.) and compared it with that of a synthetic-peptide-based EIA (Biochem Immunosystems, Montreal, Quebec, Canada) for the detection of human immunodeficiency type 1 (HIV-1) and HIV-2 antibodies in 2,321 clinical serum samples. The results of both EIA methods and Western blot (immunoblot) were in agreement for 1,046 HIV-1 and 10 HIV-2 specimens from a panel of known positives. From a prospective panel of 1,085 specimens, 38 proved to be positive by both EIAs and Western blot, 3 were positive by the recombinant EIA only, and 9 were positive by the peptide EIA only, for calculated specificities of 99.71 and 99.04%, respectively. Of 180 specimens from a seroconversion panel collected from 77 patients, the results for 170 were in agreement by all antibody testing methods and 10 were found to be repeat reactive for HIV antibodies by the recombinant EIA only. All 10 were initial specimens of seroconverting patients; 7 were also reactive for HIV p24 antigen. An examination of four of these sera by radioimmunoprecipitation assay showed gp120 and gp160 bands in each. Analysis of the anti-Env antibody class in three of these samples showed that one consisted of immunoglobulin M (IgM) only and two contained both IgG and IgM antibodies. Although both EIA procedures were sensitive and specific in the detection of antibodies to HIV-1 and HIV-2 and both were capable of detecting early antibodies, the recombinant assay was more sensitive for antibody detection during early seroconversion.