HIV SeropositivityHIV SeroprevalenceFluorescent Antibody TechniqueHIV InfectionsAntibodies, MonoclonalSubstance Abuse, IntravenousEpitopesSexual BehaviorAntibodiesRisk FactorsSeroepidemiologic StudiesAntibodies, ViralAntibodies, BacterialAntibody SpecificityAntibodies, NeutralizingAntibody FormationImmunoglobulin GAntibodies, ProtozoanAntibody AffinityEnzyme-Linked Immunosorbent AssaySerologic TestsChlamydophila pneumoniaeHIV AntibodiesImmunoglobulin MAntibodies, Anti-IdiotypicBinding Sites, AntibodyChlamydophila InfectionsCross ReactionsImmunoglobulin AHIV SeronegativityPrevalenceAntibodies, NeoplasmAntibodies, AntinuclearHelicobacter pyloriHelicobacter InfectionsAutoantibodiesAntigens, BacterialNeutralization TestsToxocariasisHIV-1Molecular Sequence DataFluorescent Antibody Technique, IndirectToxoplasmosisAntibodies, FungalAcquired Immunodeficiency SyndromeBlood DonorsCytomegalovirus InfectionsHerpesvirus 2, HumanHepatitis C AntibodiesCross-Sectional StudiesHepatitis CCase-Control StudiesToxocaraAntigen-Antibody ReactionsAntibodies, BispecificAmino Acid SequenceImmunoassayNeosporaMice, Inbred BALB CSingle-Chain AntibodiesToxoplasmaAntibodies, BlockingAIDS SerodiagnosisImmunoenzyme TechniquesSyphilisPapillomavirus InfectionsAntigen-Antibody ComplexImmunoglobulin Fab FragmentsHerpes GenitalisAntibodies, HeterophileBrazilHIV AntigensAntibodies, CatalyticRural PopulationAge FactorsHomosexualityHepatitis ABlotting, WesternHepatitis BHepatitis A Virus, HumanCytomegalovirusHuman papillomavirus 16RabbitsHepatitis B AntibodiesTime FactorsChlamydia InfectionsSensitivity and SpecificityAntibodies, Monoclonal, HumanizedPregnancyAntigens, ViralCohort StudiesHybridomasImmune SeraEpitope Mapping