RESUMO
We have used a virus-binding assay to examine conformational changes that occur when soluble CD4 (sCD4) binds to the surface of intact, native, primary human immunodeficiency virus type 1 virions. The isolates examined belong to seven genetic clades (A to H) and are representative of syncytium-inducing and non-syncytium-inducing phenotypes. Conformational changes in epitopes in the C2, V2, V3, C5, and CD4 binding domain (CD4bd) of gp120 and the cluster I and II regions of gp41 of these viruses were examined using human monoclonal antibodies that are directed at these regions. The studies revealed that sCD4 binding causes a marked increase in exposure of epitopes in the V3 loop, irrespective of the clade or the phenotype of the virus. Sporadic increases in exposure were observed in some epitopes in the V2 region, while no changes were observed in the C2, C5, or CD4bd of gp120 or the cluster I and II regions of gp41.
Assuntos
Antígenos CD4/química , HIV-1/química , HIV-1/genética , Antígenos CD4/metabolismo , HIV-1/metabolismo , Humanos , Ligação Proteica , Vírion/química , Vírion/genética , Vírion/metabolismo , Replicação ViralRESUMO
This protocol describes a simple assay that can be used to study the nature of exposure of antigenic epitopes and antigenic relatedness of different intact, native HIV-1 strains. The assay is based on the principle that mAbs coated on microtiter wells bind to epitopes on the surface of intact, native virions. The bound virion is then lysed to release p24, which is then quantitated (pg/ml) to give a measure of the amount of virion bound to the mAb. High p24 levels released after lysis correlate with high level capture of virions by mAbs, and as such, reflect good exposure of the epitope on the virion. Likewise, binding patterns of a specific mAb with different virus strains reveal information on their antigenic relatedness. In establishing this assay, the nature of exposure of antigenic epitopes and the antigenic relatedness of six intact, native HIV-1 virions of clades A, B, C, D, F and G were examined using anti-HIV-1 mAbs directed at epitopes in the V2, V3, CD4bd and C5 of gp120, and in clusters I and II of the gp41 region. Analysis of the binding data shows that mAbs directed at epitopes in the V3, C5 and gp41 Cluster I region bound best to the viruses examined, suggesting that these are the regions most exposed and conserved on intact, native HIV-1 virions of different clades. Epitopes in the V2 and CD4bd of gp120, and in gp41 cluster II, are not exposed on intact, native virions.
Assuntos
Ensaio de Imunoadsorção Enzimática/métodos , Proteína do Núcleo p24 do HIV/imunologia , HIV-1/imunologia , Anticorpos Monoclonais/imunologia , Células Cultivadas , Sequência Conservada , Epitopos/imunologia , Anticorpos Anti-HIV/imunologia , Proteína gp120 do Envelope de HIV/imunologia , Proteína gp41 do Envelope de HIV/imunologia , Humanos , Especificidade da Espécie , Vírion/imunologiaRESUMO
The relative resistance of human immunodeficiency virus type 1 (HIV-1) primary isolates (PIs) to neutralization by a wide range of antibodies remains a theoretical and practical barrier to the development of an effective HIV vaccine. One model to account for the differential neutralization sensitivity between Pls and laboratory (or T-cell line-adapted [TCLA]) strains of HIV suggests that the envelope protein (Env) complex is made more accessible to antibody binding as a consequence of adaptation to growth in established cell lines. Here, we revisit this question using genetically related PI and TCLA viruses and molecularly cloned env genes. By using complementary techniques of flow cytometry and virion binding assays, we show that monoclonal antibodies targeting the V3 loop, CD4-binding site, CD4-induced determinant of gp120, or the ectodomain of gp41 bind equally well to PI and TCLA Env complexes, despite large differences in neutralization outcome. The data suggest that the differential neutralization sensitivity of PI and TCLA viruses may derive not from differences in the initial antibody binding event but rather from differences in the subsequent functioning of the PI and TCLA Envs during virus entry. An understanding of these as yet undefined differences may enhance our ability to generate broadly neutralizing HIV vaccine immunogens.
Assuntos
Anticorpos Monoclonais/imunologia , Anticorpos Anti-HIV/imunologia , Infecções por HIV/virologia , HIV-1/imunologia , Afinidade de Anticorpos , Linhagem Celular , Citometria de Fluxo , Produtos do Gene env/imunologia , Infecções por HIV/imunologia , HIV-1/metabolismo , HIV-1/patogenicidade , Humanos , Testes de Neutralização , Linfócitos T/virologia , Transfecção , Vírion/imunologia , Vírion/patogenicidadeRESUMO
In order to protect against organisms that exhibit significant genetic variation, polyvalent vaccines are needed. Given the extreme variability of human immunodeficiency virus type 1 (HIV-1), it is probable that a polyvalent vaccine will also be needed for protection from this virus. However, to understand how to construct a polyvalent vaccine, serotypes or immunotypes of HIV must be identified. In the present study, we have examined the immunologic relatedness of intact, native HIV-1 primary isolates of group M, clades A to H, with human monoclonal antibodies (MAbs) directed at epitopes in the V3, C5, and gp41 cluster I regions of the envelope glycoproteins, since these regions are well exposed on the virion surface. Multivariate analysis of the binding data revealed three immunotypes of HIV-1 and five MAb groups useful for immunotyping of the viruses. The analysis revealed that there are fewer immunotypes than genotypes of HIV and that clustering of the isolates did not correlate with either genotypes, coreceptor usage (CCR5 and CXCR4), or geographic origin of the isolates. Further analysis revealed distinct MAb groups that bound preferentially to HIV-1 isolates belonging to particular immunotypes or that bound to all three immunotypes; this demonstrates that viral immunotypes identified by mathematical analysis are indeed defined by their immunologic characteristics. In summary, these results indicate (i) that HIV-1 immunotypes can be defined, (ii) that constellations of epitopes that are conserved among isolates belonging to each individual HIV-1 immunotype exist and that these distinguish each of the immunotypes, and (iii) that there are also epitopes that are routinely shared by all immunotypes.
Assuntos
Antígenos HIV/imunologia , Infecções por HIV/virologia , HIV-1/classificação , HIV-1/imunologia , Vírion/imunologia , Anticorpos Monoclonais/imunologia , Anticorpos Monoclonais/metabolismo , Análise por Conglomerados , Genótipo , Proteína gp120 do Envelope de HIV/imunologia , Proteína gp41 do Envelope de HIV/imunologia , HIV-1/genética , HIV-1/metabolismo , HumanosRESUMO
We have examined the exposure and conservation of antigenic epitopes on the surface envelope glycoproteins (gp120 and gp41) of 26 intact, native, primary human immunodeficiency virus type 1 (HIV-1) group M virions of clades A to H. For this, 47 monoclonal antibodies (MAbs) derived from HIV-1-infected patients were used which were directed at epitopes of gp120 (specifically V2, C2, V3, the CD4-binding domain [CD4bd], and C5) and epitopes of gp41 (clusters I and II). Of the five regions within gp120 examined, MAbs bound best to epitopes in the V3 and C5 regions. Only moderate to weak binding was observed by most MAbs to epitopes in the V2, C2, and CD4bd regions. Two anti-gp41 cluster I MAbs targeted to a region near the tip of the hydrophilic immunodominant domain bound strongly to >90% of isolates tested. On the other hand, binding of anti-gp41 cluster II MAbs was poor to moderate at best. Binding was dependent on conformational as well as linear structures on the envelope proteins of the virions. Further studies of neutralization demonstrated that MAbs that bound to virions did not always neutralize but all MAbs that neutralized bound to the homologous virus. This study demonstrates that epitopes in the V3 and C5 regions of gp120 and in the cluster I region of gp41 are well exposed on the surface of intact, native, primary HIV-1 isolates and that cross-reactive epitopes in these regions are shared by many viruses from clades A to H. However, only a limited number of MAbs to these epitopes on the surface of HIV-1 isolates can neutralize primary isolates.
Assuntos
Epitopos/imunologia , Proteína gp120 do Envelope de HIV/imunologia , Proteína gp41 do Envelope de HIV/imunologia , Infecções por HIV/virologia , HIV-1/imunologia , Vírion/imunologia , Sequência de Aminoácidos , Anticorpos Monoclonais/imunologia , Anticorpos Monoclonais/metabolismo , Sequência Conservada , Mapeamento de Epitopos , Epitopos/química , Anticorpos Anti-HIV/imunologia , Anticorpos Anti-HIV/metabolismo , Infecções por HIV/imunologia , HIV-1/classificação , HIV-1/metabolismo , Humanos , Leucócitos Mononucleares/virologia , Dados de Sequência Molecular , Testes de Neutralização , Conformação Proteica , Vírion/patogenicidadeRESUMO
Because immunologic classification of human immunodeficiency virus type 1 (HIV) might be more relevant than genotypic classification for designing polyvalent vaccines, studies were undertaken to determine whether immunologically defined groups of HIV ("immunotypes") could be identified. For these experiments, the V3 region of the 120-kDa envelope glycoprotein (gp120) was chosen for study. Although antibodies (Abs) to V3 may not play a major protective role in preventing HIV infection, identification of a limited number of immunologically defined structures in this extremely variable region would set a precedent supporting the hypothesis that, despite its diversity, the HIV family, like the V3 region, might be divisible into immunotypes. Consequently, the immunochemical reactivities of 1,176 combinations of human anti-V3 monoclonal Abs (MAbs) and V3 peptides, derived from viruses of several clades, were studied. Extensive cross-clade reactivity was observed. The patterns of reactivities of 21 MAbs with 50 peptides from clades A through H were then analyzed by a multivariate statistical technique. To test the validity of the mathematical approach, a cluster analysis of the 21 MAbs was performed. Five groups were identified, and these MAb clusters corresponded to classifications of these same MAbs based on the epitopes which they recognize. The concordance between the MAb clusters identified by mathematical analysis and by their specificities supports the validity of the mathematical approach. Therefore, the same mathematical technique was used to identify clusters within the 50 peptides. Seven groups of peptides, each containing peptides from more than one clade, were defined. Inspection of the amino acid sequences of the peptides in each of the mathematically defined peptide clusters revealed unique "signature sequences" that suggest structural motifs characteristic of each V3-based immunotype. The results suggest that cluster analysis of immunologic data can define immunotypes of HIV. These immunotypes are distinct from genotypic classifications. The methods described pave the way for identification of immunotypes defined by immunochemical and neutralization data generated with anti-HIV Env MAbs and intact, viable HIV virions.
Assuntos
Anticorpos Anti-HIV/imunologia , Proteína gp120 do Envelope de HIV/imunologia , HIV-1/classificação , HIV-1/imunologia , Fragmentos de Peptídeos/imunologia , Anticorpos Monoclonais/imunologia , Proteína gp120 do Envelope de HIV/classificação , Humanos , Fragmentos de Peptídeos/classificaçãoRESUMO
The reactivity of human monoclonal and polyclonal anti-HIV-1 antibodies demonstrates that shared epitopes, including those that induce neutralizing antibodies, exist and are recognized by the human immune system. A priori, there is no reason why cross-clade neutralizing antibodies could not be induced by an appropriately constructed HIV vaccine. But to construct such a vaccine, it is critical to understand, as completely as possible, the antigenic structure of HIV, to establish and identify immunologic classifications for HIV, and to choose rationally the minimum number and types of viruses from these immunologic groupings that will induce the broadest protective responses.
Assuntos
Vacinas contra a AIDS , Variação Antigênica/imunologia , Antígenos HIV/imunologia , HIV-1/imunologia , Sequência de Aminoácidos , Anticorpos Monoclonais/imunologia , Reações Cruzadas , Anticorpos Anti-HIV/imunologia , Proteína gp120 do Envelope de HIV/imunologia , Proteína gp160 do Envelope de HIV/imunologia , Infecções por HIV/imunologia , Humanos , Dados de Sequência Molecular , Testes de Neutralização , Fragmentos de Peptídeos/imunologiaRESUMO
Accumulating data in human immunodeficiency virus (HIV)-infected individuals support the hypothesis that in primary human immunodeficiency virus type 1 (HIV-1) isolates of different clades and phenotype (syncytium inducing [SI] and nonsyncytium inducing [NSI]) common antigenic structures must exist that can stimulate the immune response to produce a broad spectrum (cross-clade and cross SI and NSI) neutralization response. Certain vaccination regimens in chimpanzees and human volunteers with clade B SI type HIV-1 derived candidate vaccines induce neutralizing antibodies against intraclade B SI type primary HIV-1 isolates, but not against intraclade B NSI type of viruses. To be effective against the full antigenic spectrum of primary HIV-1 isolates (cross-clade--SI and NSI) candidate vaccines should contain immunogens of primary isolates representative of the whole antigenic spectrum of HIV-1. There is an urgent need to identify these immunogens and to improve their immunogenicity. As long as we have not yet characterized these cross-HIV-1 spectrum conserved immunogens, candidate vaccines against the more prevalent clades C, A, and E should be developed for evaluation in developing countries. In support of the follow-up and evaluation of the hopefully increasing number of phase 1, 2, and 3 HIV-1 vaccine trials in humans, it is considered a high priority to develop a high throughput neutralization assay, to further expand the use of a limited number of key primary HIV-1 isolates as a surrogate for neutralization of the entire HIV-1 antigenic spectrum (cross-clade--SI and NSI), to develop high throughput subtyping as well as a rapid system to monitor the immunogenic relatedness of different HIV-1 clades.
Assuntos
Vacinas contra a AIDS , Variação Genética , HIV-1/genética , Desenho de Fármacos , Avaliação de Medicamentos , HIV-1/imunologia , Especificidade da EspécieRESUMO
To study the antigenic conservation of epitopes of human immunodeficiency virus type 1 (HIV-1) isolates of different clades, the abilities of human anti-HIV-1 gp120 and gp41 monoclonal antibodies (MAbs) to bind to intact HIV-1 virions were determined by a newly developed virus-binding assay. Eighteen human anti-HIV MAbs, which were directed at the V2, V3 loop, CD4-binding domain (CD4bd), C5, or gp41 regions, were used. Nine HIV-1 isolates from clades A, B, D, F, G, and H were used. Microtiter wells were coated with the MAbs, after which virus was added. Bound virus was detected after lysis by testing for p24 antigen with a noncommercial p24 enzyme-linked immunosorbent assay. The anti-V3 MAbs strongly bound the four clade B viruses and viruses from the non-B clades, although binding was weaker and more sporadic with the latter. The degrees of binding by the anti-V3 MAbs to CXCR4- and CCR5-tropic viruses were similar, suggesting that the V3 loops of these two categories of viruses are similarly exposed. The anti-C5 MAbs bound isolates of clades A, B, and D. Only weak and sporadic binding of all the viruses tested with anti-CD4bd, anti-V2, and anti-gp41 MAbs was detected. These results suggest that V3 and C5 structures are shared and well exposed on intact virions of different clades compared to the CD4bd, V2, and gp41 regions.
Assuntos
Mapeamento de Epitopos , Antígenos HIV , HIV-1/imunologia , Anticorpos Monoclonais , Sequência Conservada , Ensaio de Imunoadsorção Enzimática , Anticorpos Anti-HIV , Antígenos HIV/genética , Proteína gp120 do Envelope de HIV/imunologia , Proteína gp41 do Envelope de HIV/imunologia , HIV-1/classificação , HIV-1/genética , Humanos , Técnicas In Vitro , Fragmentos de Peptídeos/imunologiaRESUMO
Here we report on the use of spectral map analysis of time-paired sequential neutralization data of 11 serum samples of a chimpanzee naturally infected with a simian immunodeficiency virus (SIVcpz-ant) and 8 primary consecutive SIVcpz-ant isolates, taken at about 4-month intervals. The analysis reveals the existence of three SIVcpz-ant isolate and serum neutralization clusters. Each cluster groups virus isolates and/or sera based on similarities of their neutralization spectra. On average, neutralization escape mutants emerged after 15 months and mounted a neutralization response approximately 8 months later. The entire gp160 regions of eight consecutive isolates were sequenced and analyzed by a new statistical method called polygram, which allowed the deduction of amino acid sequence motifs of gp160 which were specific for SIVcpz-ant isolates belonging to the same isolate neutralization clusters. Changes in specific amino acid quadruplets in V1, V2, C3, V4, V5, and CD4 domains of gp120 and gp40 were seen to correlate with the neutralization clusters with most of the specific changes occurring in the V4 region. This method of analysis may facilitate an understanding of the study of the dynamic interplay between human immunodeficiency virus (HIV) and host neutralization responses as well as providing possible insights into mechanisms of persistence of HIV-1-related lentiviruses in their natural hosts.
Assuntos
Anticorpos Antivirais/imunologia , Produtos do Gene env/genética , Síndrome de Imunodeficiência Adquirida dos Símios/imunologia , Síndrome de Imunodeficiência Adquirida dos Símios/virologia , Vírus da Imunodeficiência Símia/genética , Vírus da Imunodeficiência Símia/imunologia , Proteínas do Envelope Viral , Sequência de Aminoácidos , Animais , Sequência de Bases , DNA Viral , Produtos do Gene env/imunologia , Proteína gp120 do Envelope de HIV/genética , Proteína gp120 do Envelope de HIV/imunologia , Glicoproteínas de Membrana/genética , Glicoproteínas de Membrana/imunologia , Dados de Sequência Molecular , Testes de Neutralização , Pan troglodytes , Proteínas dos Retroviridae/genética , Proteínas dos Retroviridae/imunologia , Análise de Sequência de DNA , Síndrome de Imunodeficiência Adquirida dos Símios/sangue , Vírus da Imunodeficiência Símia/isolamento & purificaçãoRESUMO
Neutralizing antibody (NA) patterns in the sera of individuals naturally infected with human immunodeficiency virus (HIV) type 1, HIV-2, and the simian immunodeficiency virus (SIVcpz) to their homologous and heterologous isolates were determined in a peripheral blood mononuclear cell-based neutralization assay. We examined the role of the V3 loop of HIV-1 and SIVcpz in neutralization and the cross-reactivities among them. Cross-neutralization by sera of humans and chimpanzees naturally infected, respectively, with HIV-1 and SIVcpz isolates was more extensive than the infrequent and low-titer cross-neutralizations observed between HIV-1 and HIV-2. Neutralization of 9 of the 16 HIV-1 isolates by 9 of 10 HIV-2 and all 3 SIVcpz antibody-positive sera were weak and sporadic (titer, 1:10-1:160). Twelve of 15 HIV-1 sera neutralized the 2 SIVcpz isolates with titers of 1:10-1:320 but only sporadically neutralized the 6 HIV-2 isolates (titers: 1:10-1:20). The majority of HIV-1 and SIVcpz sera bound to the V3 peptides although their binding capacity did not readily reflect their neutralizing capacity. The HIV-2 sera did not or only weakly bound to the V3 peptides. These results suggest that HIV-1 and SIVcpz share some structural and functional similarities that set them apart from HIV-2.
Assuntos
Variação Genética/imunologia , Anticorpos Anti-HIV/sangue , HIV-1/imunologia , HIV-2/imunologia , Vírus da Imunodeficiência Símia/imunologia , Animais , Reações Cruzadas , Proteína gp120 do Envelope de HIV/metabolismo , HIV-1/classificação , HIV-1/genética , HIV-2/classificação , HIV-2/genética , Humanos , Soros Imunes , Dados de Sequência Molecular , Testes de Neutralização , Pan troglodytes , Fragmentos de Peptídeos/metabolismo , Filogenia , Sorotipagem , Vírus da Imunodeficiência Símia/classificação , Vírus da Imunodeficiência Símia/genéticaRESUMO
We report on the use of spectral map analysis of the inter- and intraclade neutralization data of 14 sera of human immunodeficiency virus type 1 (HIV-1)-infected individuals and 16 primary isolates, representing genetic clades A to H in group M and group O. This multivariate analysis has been used previously to study the interaction between drugs and receptors and between viruses and antiviral compounds. The analysis reveals the existence of neutralization clusters, not correlated with the known genetic clades. The structural factors that have been identified may correlate with the most important neutralization epitopes. Three key primary HIV-1 isolates, which allow discrimination of sera that are likely or unlikely to neutralize primary isolates from most of the genetic clades, were identified. Our method of analysis will facilitate the evaluation as well as the design of suitable HIV-1 vaccines, which induce high-titer interclade cross-neutralizing antibodies.
Assuntos
Síndrome da Imunodeficiência Adquirida/imunologia , Anticorpos Anti-HIV/sangue , Infecções por HIV/imunologia , HIV-1/imunologia , Síndrome da Imunodeficiência Adquirida/sangue , Algoritmos , Especificidade de Anticorpos , Infecções por HIV/sangue , HIV-1/classificação , HIV-1/genética , HIV-2/imunologia , Humanos , Análise Multivariada , Testes de Neutralização , Vírus da Imunodeficiência Símia/imunologiaRESUMO
SUMMARY: For 4 years. we determined the mode and risk of mother-to-child transmission of HTLV-I in a prospective cohort of 34 children born to seropositive mothers in Franceville, Gabon. We also determined the prevalence of antibodies to HTLV-I/II in siblings born to seropositive mothers. Antibodies to HTLV-I/II were detected by Western blot, and the proviral DNA was detected by the polymerase chain reaction (PCR). The risk of seroconversion to anti-HTLV-I for the 4 years of follow-up was 17.5 percent. Anti-HTLV-I/II and proviral DNA were only detected after age 18 months. We observed a seroprevalence rate of 15 percent among the siblings born to HTLV-I/II seropositive mothers. Furthermore, we report a case of mother-to-child transmission of HTLV-II infection in a population of HTLV-II-infected pregnant women that is emerging in Gabon. The lack of detection of HTLV-I/II proviral DNA in cord blood and amniotic fluid and, furthermore, the late seroconversion observed in the children indirectly indicate that mother-to-child transmission occurred postnatally, probably through breast milk.
Assuntos
Infecções por HTLV-I/transmissão , Infecções por HTLV-II/transmissão , Líquido Amniótico/virologia , Western Blotting , Pré-Escolar , Estudos de Coortes , DNA Viral/genética , DNA Viral/isolamento & purificação , Feminino , Seguimentos , Gabão/epidemiologia , Anticorpos Anti-HTLV-I/sangue , Infecções por HTLV-I/epidemiologia , Infecções por HTLV-I/imunologia , Anticorpos Anti-HTLV-II/sangue , Infecções por HTLV-II/epidemiologia , Infecções por HTLV-II/imunologia , Vírus Linfotrópico T Tipo 1 Humano/genética , Vírus Linfotrópico T Tipo 1 Humano/isolamento & purificação , Vírus Linfotrópico T Tipo 2 Humano/genética , Vírus Linfotrópico T Tipo 2 Humano/isolamento & purificação , Humanos , Lactente , Recém-Nascido , Transmissão Vertical de Doenças Infecciosas , Troca Materno-Fetal , Reação em Cadeia da Polimerase , Gravidez , Estudos Prospectivos , Provírus/genética , Provírus/isolamento & purificaçãoRESUMO
Neutralizing antibody patterns in sera of persons infected with human immunodeficiency virus type 1 (HIV-1) groups M and O to their homologous and heterologous primary isolates were determined in a peripheral blood mononuclear cell-based neutralization assay and correlated with their ability to bind to V3 loop synthetic peptides. Most HIV-1 group M sera (9/16) neutralized HIV-1 group O viruses, whereas fewer group O sera (3/13) only weakly neutralized HIV-1 group M viruses. Group M sera neutralizing HIV-1 group O viruses neutralized other HIV-1 group M viruses with titers of 1:10-1:1280. V3 loop binding capacity of sera did not reflect their neutralizing capacity of the homologous isolate. Despite the reduced neutralizing capacity of group O-infected patients' sera to group M viruses, some group M-infected patients' sera neutralized both HIV-1 group M and O isolates, suggesting that they share some conserved neutralizing epitopes.
Assuntos
Síndrome da Imunodeficiência Adquirida/imunologia , Epitopos/imunologia , Produtos do Gene env/imunologia , Anticorpos Anti-HIV/imunologia , HIV-1/classificação , HIV-1/imunologia , Linfócitos/imunologia , Síndrome da Imunodeficiência Adquirida/sangue , Sequência de Aminoácidos , Western Blotting , Ensaio de Imunoadsorção Enzimática , Epitopos/química , Produtos do Gene env/genética , Genes env , Genes gag , Anticorpos Anti-HIV/sangue , HIV-1/isolamento & purificação , Humanos , Linfócitos/virologia , Dados de Sequência Molecular , Testes de Neutralização , Fragmentos de Peptídeos/síntese química , Fragmentos de Peptídeos/química , Fragmentos de Peptídeos/imunologia , FilogeniaRESUMO
The human immunodeficiency virus type 1 (HIV-1) DNA PCR results of 94 dried blood spot (DBS) samples on filter paper and corresponding venous blood in EDTA obtained from infants born to HIV-1-seropositive mothers were compared. In addition, the results of HIV-1 DNA PCR on DBS and the HIV-1 RNA PCR from plasma of 70 paired samples were compared. A 100% specificity and a 95% sensitivity for HIV-1 DNA PCR on DBS compared with results for venous blood were observed for the 94 paired samples. The results of the DBS HIV-1 DNA PCR and HIV-1 RNA PCR of 70 corresponding plasma samples correlated perfectly (100%). The DBS HIV-1 DNA PCR method proved reliable for HIV-1 detection.