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International audience; Background: Global HIV-1 genetic diversity and evolution form a major challenge to treatment and prevention efforts. An increasing number of distinct HIV-1 recombinants have been identified worldwide, but their contribution to the global epidemic is unknown. We aimed to estimate the global and regional distribution of HIV-1 recombinant forms during 1990-2015.Methods: We assembled a global HIV-1 molecular epidemiology database through a systematic literature review and a global survey. We searched the PubMed, Embase (Ovid), CINAHL (Ebscohost), and Global Health (Ovid) databases for HIV-1 subtyping studies published from Jan 1, 1990, to Dec 31, 2015. Unpublished original HIV-1 subtyping data were collected through a survey among experts in the field who were members of the WHO-UNAIDS Network for HIV Isolation and Characterisation. We included prevalence studies with HIV-1 subtyping data collected during 1990-2015. Countries were grouped into 14 regions and analyses were done for four time periods (1990-99, 2000-04, 2005-09, and 2010-15). The distribution of circulating recombinant forms (CRFs) and unique recombinant forms (URFs) in individual countries was weighted according to the UNAIDS estimates of the number of people living with HIV in each country to generate regional and global estimates of numbers and proportions of HIV-1 recombinants in each time period. The systematic review is registered with PROSPERO, CRD42017067164.Findings: Our global data collection yielded an HIV-1 molecular epidemiology database of 383 519 samples from 116 countries in 1990-2015. We found that the proportion of recombinants increased over time, both globally and in most regions, reaching 22·8% (7 978 517 of 34 921 639) of global HIV-1 infections in 2010-15. Both the proportion and the number of distinct CRFs detected increased over time to 16·7% and 57 CRFs in 2010-15. The global and regional distribution of HIV-1 recombinants was diverse and evolved over time, and we found large regional variation in the numbers (0-44 CRFs), types (58 distinct CRFs), and proportions (0-80·5%) of HIV-1 recombinants. Globally, CRF02_AG was the most prevalent recombinant, accounting for 33·9% (2 701 364 of 7 978 517) of all recombinant infections in 2010-15. URFs accounted for 26·7% (2 131 450 of 7 978 517), CRF01_AE for 23·0% (1 838 433), and other CRFs for 16·4% (1 307 270) of all recombinant infections in 2010-15. Although other CRFs accounted for small proportions of infections globally (

Background HIV-1 Integrase (IN) interacts with the cellular co-factor LEDGF/p75 and tethers the HIV preintegration complex to the host genome enabling integration. Recently a new class of IN inhibitors was described, the IN-LEDGF allosteric inhibitors (INLAIs). Designed to interfere with the IN-LEDGF interaction during integration, the major impact of these inhibitors was surprisingly found on virus maturation, causing a reverse transcription defect in target cells. Results Here we describe the MUT-A compound as a genuine INLAI with an original chemical structure based on a new type of scaffold, a thiophene ring. MUT-A has all characteristics of INLAI compounds such as inhibition of IN-LEDGF/p75 interaction, IN multimerization, dual antiretroviral (ARV) activities, normal packaging of genomic viral RNA and complete Gag protein maturation. MUT-A has more potent ARV activity compared to other INLAIs previously reported, but similar profile of resistance mutations and absence of ARV activity on SIV. HIV-1 virions produced in the presence of MUT-A were non-infectious with the formation of eccentric condensates outside of the core. In studying the immunoreactivity of these non-infectious virions, we found that inactivated HIV-1 particles were captured by anti-HIV-specific neutralizing and non-neutralizing antibodies (b12, 2G12, PGT121, 4D4, 10-1074, 10E8, VRC01) with efficiencies comparable to non-treated virus. Autologous CD4+ T lymphocyte proliferation and cytokine induction by monocyte-derived dendritic cells (MDDC) pulsed either with MUT-A-inactivated HIV or non-treated HIV were also comparable. Conclusions Although strongly defective in infectivity, HIV-1 virions produced in the presence of the MUT-A INLAI have a normal protein and genomic RNA content as well as B and T cell immunoreactivities comparable to non-treated HIV-1. These inactivated viruses might form an attractive new approach in vaccine research in an attempt to study if this new type of immunogen could elicit an immune response against HIV-1 in animal models. Electronic supplementary material The online version of this article (10.1186/s12977-017-0373-2) contains supplementary material, which is available to authorized users.

PURPOSE OF REVIEW Increased body of evidence gathered over time indicate that antibodies are capable of many inhibitory mechanisms, virus neutralization being just one of them. Nonneutralizing antibodyactivities interfering with HIV replication can also lead to a decrease in viral load and even in-vivo protection. RECENT FINDINGS It was previously believed that neutralizing antibodies can achieve sterilizing protection mainly by using their neutralization capacities against the infecting virus directly at the portal of virus entry. Recent findings show that protection can be obtained by neutralizing antibodiesat distal sites of virus challenge. In this case, foci of virus infection that escaped from initial inhibition of virus are eliminated presumably by additional nonneutralizing antibody activities. These data inexorably strengthen the diverse functions of antibodies and broaden their role as antiviral mediator. SUMMARY The review summarizes the current knowledge and the difficulties to encompass the numerous functions of antibodies. A complete understanding of the various facets of antibody functions is required to efficiently induce them via next-generation vaccine design.

The results of the RV144 vaccine clinical trial showed a correlation between high level of anti-V1V2 antibodies (Abs) and a decreased risk of acquiring HIV-1 infection. This turned the focus of HIV vaccine design to the induction of elevated levels of anti-V2 Abs to increase vaccine efficacy. In plasma samples from HIV-1 infected Cameroonian individuals, we observed broad variations in levels of anti-V2 Abs, and 6 of the 79 plasma samples tested longitudinally displayed substantial deficiency of V2 Abs. Sequence analysis of the V2 region from plasma viruses and multivariate analyses of V2 characteristics showed a significant difference in several features between V2-deficient and V2-reactive plasma Abs. These results suggest that HIV vaccine immunogens containing a shorter V2 region with fewer glycosylation sites and higher electrostatic charges can be beneficial for induction of a higher level of anti-V2 Abs and thus contribute to HIV vaccine efficacy.

The positive correlation of high levels of plasma anti-V2 antibodies (Abs) with protective immunity in the Phase III anti-HIV RV144 vaccine trial generated interest in the induction of these Abs for HIV vaccine development. We analyzed plasma samples from 79 chronically infected Cameroonian individuals for Ab reactivity against three V1V2 fusion proteins and five cyclic V2 peptides and found that HIV-1 infection induces different levels of anti-V2 Abs. While the majority of plasma samples reacted strongly with one or more V2 antigens, 10% (8) of the samples were nonreactive. Deficiency of anti-V2 Abs was consistently found in longitudinal plasma samples tested over 8 to 54 months of HIV infection. There was a strong correlation between binding activities of plasma anti-V2 Abs and anti-gp120 and anti-gp41 Abs, suggesting that deficiency of V2 Abs could be related, in part, to a limited ability to elicit strong Ab responses. Analysis of gp120 sequences revealed that the V2 region of viruses from donors with V2-deficient versus V2-reactive Abs displayed a tendency toward longer length, more glycans, and lower isoelectric point and charge. No differences between these two patient groups were noted in the same parameters measured in the V1 region. These data suggest that immunogens containing a shorter V2 region with fewer glycosylation sites and higher electrostatic charges would be beneficial for induction of anti-V2 Abs, but the ability to mount a strong general Ab response to HIV-1 appears to be a dominant factor.IMPORTANCEThe results of the RV144 vaccine clinical trial showed a correlation between plasma Abs against a V1V2 fusion protein and a decreased risk of acquiring HIV-1 infection. This turned the focus of some HIV vaccine design to the induction of elevated levels of anti-V2 Abs to increase vaccine efficacy. In plasma samples from Cameroonian individuals infected with HIV-1, we observed broad variations in levels of anti-V2 Abs, and 8 of the 79 plasma samples tested displayed substantial deficiency of V2 Abs. Sequence analysis of the V2 region from plasma viruses and multivariate analyses of V2 characteristics showed a significant difference in several features between V2-deficient and V2-reactive plasma Abs. These results suggest that HIV vaccine immunogens containing a V2 region with shorter length, fewer glycosylation sites, and higher electrostatic charges may be beneficial for induction of a higher level of anti-V2 Abs and thus contribute to HIV vaccine efficacy.

The V3 region of HIV-1 gp120 is important for virus-coreceptor interaction and highly immunogenic. Although most anti-V3 antibodies neutralize only the sensitive tier 1 viruses, anti-V3 antibodies effective against the more resistant viruses exist, and a better understanding of these antibodies and their epitopes would be beneficial for the development of novel vaccine immunogens against HIV. The HIV-1 isolate JRFL with its cryptic V3 is resistant to most V3-specific monoclonal antibodies (MAbs). However, the V3 MAb 2424 achieves 100% neutralization against JRFL. 2424 is encoded by IGHV3-53 and IGLV2-28 genes, a pairing rarely used by the other V3 MAbs. 2424 also has distinct binding and neutralization profiles. Studies of 2424-mediated neutralization of JRFL produced with a mannosidase inhibitor further revealed that its neutralizing activity is unaffected by the glycan composition of the virus envelope. To understand the distinct activity of 2424, we determined the crystal structure of 2424 Fab in complex with a JRFL V3 peptide and showed that the 2424 epitope is located at the tip of the V3 crown ( 307 IHIGPGRAFYT 319 ), dominated by interactions with His P308 , Pro P313 , and Arg P315 . The binding mode of 2424 is similar to that of the well-characterized MAb 447-52D, although 2424 is more side chain dependent. The 2424 epitope is focused on the very apex of V3, away from nearby glycans, facilitating antibody access. This feature distinguishes the 2424 epitope from the other V3 crown epitopes and indicates that the tip of V3 is a potential site to target and incorporate into HIV vaccine immunogens. IMPORTANCE HIV/AIDS vaccines are crucial for controlling the HIV epidemics that continue to afflict millions of people worldwide. However, HIV vaccine development has been hampered by significant scientific challenges, one of which is the inability of HIV vaccine candidates evaluated thus far to elicit production of potent and broadly neutralizing antibodies. The V3 loop is one of the few immunogenic targets on the virus envelope glycoprotein that can induce neutralizing antibodies, but in many viruses, parts of V3 are inaccessible for antibody recognition. This study examined a V3-specific monoclonal antibody that can completely neutralize HIV-1 JRFL, a virus isolate resistant to most V3 antibodies. Our data reveal that this antibody recognizes the most distal tip of V3, which is not as occluded as other parts of V3. Hence, the epitope of 2424 is in one of the vulnerable sites on the virus that may be exploited in designing HIV vaccine immunogens.

HIV superinfection describes the sequential infection of an individual with two or more unrelated HIV strains. Intersubtype superinfection has been shown to cause a broader and more potent heterologous neutralizing antibody response when compared to singly infected controls, yet the effects of intrasubtype superinfection remain controversial. Longitudinal samples were analyzed phylogenetically for pol and env regions using Next-Generation Sequencing and envelope cloning. The impact of CRF02_AG intrasubtype superinfection was assessed for heterologous neutralization and antibody binding responses. We compared two cases of CRF02_AG intrasubtype superinfection that revealed complete replacement of the initial virus by superinfecting CRF02_AG variants with signs of recombination. NYU6564, who became superinfected at an early time point, exhibited greater changes in antibody binding profiles and generated a more potent neutralizing antibody response post-superinfection compared to NYU6501. In contrast, superinfection occurred at a later time point in NYU6501 with strains harboring significantly longer V1V2 regions with no observable changes in neutralization patterns. Here we show that CRF02_AG intrasubtype superinfection can induce a cross-subtype neutralizing antibody response, and our data suggest timing and/or superinfecting viral envelope characteristics as contributing factors. These results highlight differential outcomes in intrasubtype superinfection and provide the first insight into cases with CRF02_AG, the fourth most prevalent HIV-1 strain worldwide.

Broadly neutralizing antibodies targeting the HIV-1 envelope (Env) are key components for protection against HIV-1. However, many cross-reactive epitopes are often occluded. This study investigates the mechanisms contributing to the masking of V2i (variable loop V2 integrin) epitopes compared to the accessibility of V3 epitopes. V2i are conformation-dependent epitopes encompassing the integrin α4β7-binding motif on the V1V2 loop of HIV-1 Env gp120. The V2i monoclonal antibodies (MAbs) display extensive cross-reactivity with gp120 monomers from many subtypes but neutralize only few viruses, indicating V2i's cryptic nature. First, we asked whether CD4-induced Env conformational changes affect V2i epitopes similarly to V3. CD4 treatment of BaL and JRFL pseudoviruses increased their neutralization sensitivity to V3 MAbs but not to the V2i MAbs. Second, the contribution of N-glycans in masking V2i versus V3 epitopes was evaluated by testing the neutralization of pseudoviruses produced in the presence of a glycosidase inhibitor, kifunensine. Viruses grown in kifunensine were more sensitive to neutralization by V3 but not V2i MAbs. Finally, we evaluated the time-dependent dynamics of the V2i and V3 epitopes. Extending the time of virus-MAb interaction to 18 h before adding target cells increased virus neutralization by some V2i MAbs and all V3 MAbs tested. Consistent with this, V2i MAb binding to Env on the surface of transfected cells also increased in a time-dependent manner. Hence, V2i and V3 epitopes are highly dynamic, but distinct factors modulate the antibody accessibility of these epitopes. The study reveals the importance of the structural dynamics of V2i and V3 epitopes in determining HIV-1 neutralization by antibodies targeting these sites. IMPORTANCE Conserved neutralizing epitopes are present in the V1V2 and V3 regions of HIV-1 Env, but these epitopes are often occluded from Abs. This study reveals that distinct mechanisms contribute to the masking of V3 epitopes and V2i epitopes in the V1V2 domain. Importantly, V3 MAbs and some V2i MAbs display greater neutralization against relatively resistant HIV-1 isolates when the MAbs interact with the virus for a prolonged period of time. Given their highly immunogenic nature, V3 and V2i epitopes are valuable targets that would augment the efficacy of HIV vaccines.

SUMMARY The interaction of T cells with dendritic cells (DCs) determines whether an immune response is launched or not. Recognition of antigen leads to formation of immunological synapses at the interface between the cells. The length of interaction is likely to determine the functional outcome, because it limits the number of MHC class II-peptide complexes that can be recruited into the synapse. Here, we show that regulatory T (Treg) cells and naive helper T (Th) cells interact differently with DCs in the absence of proinflammatory stimuli. Although differences in T cell receptor repertoire might contribute, Foxp3induced phenotypic differences play a major role. We found that Neuropilin-1 (Nrp-1), which is expressed by most Treg cells but not naive Th cells, promoted prolonged interactions with immature DCs (iDCs), resulting in higher sensitivity to limiting amounts of antigen. This is likely to give Treg cells an advantage over naive Th cells, with the same specificity leading to a ‘‘default’’ suppression of immune responses in the absence of ‘‘danger signals.’’

The MHC-encoded butyrophilin, BTN2A1, is a cell surface glycoprotein related to the extended family of B7 costimulatory molecules. BTN2A1 mRNA was expressed in most human tissues, but protein expression was significantly lower in leukocytes. An Ig-fusion protein of BTN2A1 bound to immature monocyte-derived dendritic cells. Binding diminished upon MoDC maturation and no binding was detected to Langerhans cells. Induction of the counterreceptor was IL-4 dependent and occurred early during dendritic cell differentiation. The interaction required the presence of Ca2+ and was mediated by high-mannose oligosaccharides. These properties matched DC-SIGN, a DC-specific HIV-1 entry receptor. This was confirmed by binding of soluble BTN2A1 to DC-SIGN-transfectants and its inhibition by a specific Ab. DC-SIGN bound to native BTN2A1 expressed on a range of tissues. However, BTN2A1 was not recognized on some normal cells such as HUVECs despite a similar expression level. The BTN2A1 of tumor cells such as HEK293T have more high-mannose moieties in comparison to HUVECs, and those high-mannose moieties are instrumental for binding to DC-SIGN. The data are consistent with tumor- or tissue-specific glycosylation of BTN2A1 governing recognition by DC-SIGN on immature monocyte-derived dendritic cells.

In the case-control study of the RV144 vaccine trial, the levels of antibodies to the V1V2 region of the gp120 envelope glycoprotein were found to correlate inversely with risk of HIV infection. This recent demonstration of the potential role of V1V2 as a vaccine target has catapulted this region into the focus of HIV-1 research. We previously described seven human monoclonal antibodies (mAbs) derived from HIV-infected individuals that are directed against conformational epitopes in the V1V2 domain. In this study, using lysates of SF162 pseudoviruses carrying V1V2 mutations, we mapped the epitopes of these seven mAbs. All tested mAbs demonstrated a similar binding pattern in which three mutations (F176A, Y177T, and D180L) abrogated binding of at least six of the seven mAbs to ≤15% of SF162 wildtype binding. Binding of six or all of the mAbs was reduced to ≤50% of wildtype by single substitutions at seven positions (168, 180, 181, 183, 184, 191, and 193), while one change, V181I, increased the binding of all mAbs. When mapped onto a model of V2, our results suggest that the epitope of the conformational V2 mAbs is located mostly in the disordered region of the available crystal structure of V1V2, overlapping and surrounding the α4β7 binding site on V2.

Background Cameroon is a country in West Central Africa with a population of about 20 million inhabitants, with an estimated HIV prevalence of 5.1% in the general population. The HIV epidemic in this region is marked by a broad genetic diversity dominated by Circulating Recombinant Forms (CRFs). Methods To characterize HIV-1 genotypes circulating in HIV positive individuals in Limbe, Cameroon, we phylogenetically analyzed blood samples from 116 HIV positive patients. Of 116 samples tested, 110 were amplified by nested PCR at the Gag, Pol and Env genes. Sequences obtained were phylogenetically analyzed with reference sequences from the Los Alamos database. The RT region of samples was also amplified to identify mutations that conferred resistance to Reverse Transcriptase inhibitors (RTIs) using the Stanford University Drug resistance database. Results

Background Recent studies have demonstrated that both the potency and breadth of the humoral anti-HIV-1 immune response in generating neutralizing antibodies (nAbs) against heterologous viruses are significantly enhanced after superinfection by discordant HIV-1 subtypes, suggesting that repeated exposure of the immune system to highly diverse HIV-1 antigens can significantly improve anti-HIV-1 immunity. We investigated whether sequential plasma from subjects superinfected with discordant HIV-1 subtypes, who exhibit broad nAbs against heterologous viruses, also neutralize either or both of their discordant early autologous viruses with increasing potency.

For HIV recombination to occur, the RNAs from two infecting strains within a cell must dimerize at the dimerization initiation site (DIS). We examined the sequence identity at the DIS (697-731 bp, Hxb2 numbering engine) in patients superinfected with concordant HIV-1 strains and compared them to those with discordant strains. Viral RNA in sequential plasma from four subjects superinfected with subtype-discordant and two subjects superinfected with subtype-concordant HIV-1 strains was extracted, amplified (5' LTR-early gag: 526-1200 bp, Hxb2 numbering engine), sequenced, and analyzed to determine their compatibility for dimerization in vivo. The concordant viruses infecting the two subjects exhibited identical sequences in the 35-bp-long DIS region while sequences from the discordant viruses revealed single nucleotide changes that were located in the DIS loop (715 bp), its flanking nucleotides (710 bp and 717 bp), and the DIS stem (719 bp). Evidence from in vitro experiments demonstrates that these in vivo changes identified can abolish dimerization and reduce recombination frequency. Therefore, these results revealing differences in the DIS of discordant strains versus the similarity noted for the concordant strains may contribute to the differences in the frequency of recombination in patients superinfected with such HIV-1 variants.

P34.11 LB Background: Superinfected HIV patients provide the unique opportunity to investigate the immune response after challenge with diverse HIV antigens and remain the major source for recombinant strain production. The competition and/or coexistence of two or more viral strains drive viral evolution and diversity, eventually triggering the generation of more broad and potent neutralizing antibodies (Abs) as compared to singly infected patients. The objective of this study was to analyze the genetic evolution of the viruses found within a superinfected Cameroonian patient, and to determine the neutralization sensitivity of the recombinant viruses to both autologous and heterologous neutralizing Abs. Methods: Longitudinal plasma samples from an HIV-1 superinfected Cameroonian patient were analyzed for their Env diversity, evolution, and recombination events. Pseudoviruses were generated from timepoints before, during, and after superinfection, and were then tested for sensitivity to homologous plasma and to heterologous neutralizing mAbs. Results: Env sequence analysis indicated that the CRF02_AG infected subject became superinfected with an F2 strain resulting in a massive increase in viral diversity. Later, the patient's viral repertoire was narrowed to quasispecies closely clustering with the initial strain. The highest neutralization was observed with autologous plasma from timepoints after superinfection but before the intiation of ART. Of interest, the superinfecting F2 strain was resistant to neutralization with most known broadly neutralizing antibodies (bnAbs) including PG09 and VRC01 while the original infecting CRF02_AG strain was sensitive to these bnAbs. Conclusions: The resistance of the F2 strain to known bnAbs urges the need to generate nAbs from such patients and to monitor the emerging recombinant strains. HIV-1 superinfected patients may serve for the generation of new bnAbs covering multiple subtypes and deliver important knowledge for future vaccine design.

P16.03 Background: A hallmark of HIV is its variability, which within group M viruses includes 9 subtypes and over 50 circulating recombinant forms (CRF)s. Cameroon is an epicenter of the disease known for circulation of many subtypes and CRFs, which provides a unique setting to study the immune response to HIV. It is crucial for a successful vaccine to elicit an adaptive immune response against a broad range of viral subtypes. Methods: We have performed subtype analysis of viral RNA isolated from the plasma of 63 HIV-1 infected Cameroonian subjects to verify non-B subtype infection and to monitor for recombination. From the non-B, drug naive cohort, we have isolated IgG (N=264) to screen for neutralization using a tier 2, pseudovirus panel including subtypes A1, B, C, and 01_AE. Samples capable of neutralizing multiple pseudoviruses at high potency were selected for further study to determine neutralization capacity against an extended panel and their ability to bind gp160 envelope peptides. Results: Subtypes A, D, F, G, and K were identified as well as many recombinant forms including the predominant subtype CRF02_AG. The neutralization screen concluded that 9.5% of the IgG samples were able to neutralize at least 2 pseudoviruses at low IgG concentrations. Neutralization of the extended panel revealed that these IgG samples were also able to neutralize 02_AG,G, and AC subtypes. We found that all of the broadly neutralizing IgG samples bound envelope protein gp41, over 80% bound gp120 proteins, 79% bound a scaffolded V1V2 peptide, and 100% of the samples bound cyclic V3 constructs. Conclusions: We have taken the first look at broad neutralization in a cohort infected with non-B subtype viruses and numerous CRFs. IgG from these patients is capable of neutralizing pseudoviruses across clades with high breadth and potency. We have shown that these samples bind strongly to envelope peptides and hope to continue to elucidate how these antibodies are conferring neutralization in order to guide future vaccine design.

Recent studies have demonstrated that both the potency and breadth of the humoral anti-HIV-1 immune response in generating neutralizing antibodies (nAbs) against heterologous viruses are significantly enhanced after superinfection by discordant HIV-1 subtypes, suggesting that repeated exposure of the immune system to highly diverse HIV-1 antigens can significantly improve anti-HIV-1 immunity. Thus, we investigated whether sequential plasma from these subjects superinfected with discordant HIV-1 subtypes, who exhibit broad nAbs against heterologous viruses, also neutralize their discordant early autologous viruses with increasing potency. Comparing the neutralization capacities of sequential plasma obtained before and after superinfection of 4 subjects to those of matched plasma obtained from 4 singly infected control subjects, no difference in the increase in neutralization capacity was observed between the two groups (p = 0.328). Overall, a higher increase in neutralization over time was detected in the singly infected patients (mean change in IC(50) titer from first to last plasma sample: 183.4) compared to the superinfected study subjects (mean change in IC(50) titer from first to last plasma sample: 66.5). Analysis of the Breadth-Potency Scores confirmed that there was no significant difference in the increase in superinfected and singly infected study subjects (p = 0.234). These studies suggest that while superinfection by discordant subtypes induces antibodies with enhanced neutralizing breadth and potency against heterologous viruses, the potency to neutralize their autologous viruses is not better than those seen in singly infected patients.

BACKGROUND: Global genetic diversity of HIV-1 is a major challenge to the development of HIV vaccines. We aimed to estimate the regional and global distribution of HIV-1 subtypes and recombinants during 1990-2015. METHODS: We searched PubMed, EMBASE (Ovid), CINAHL (Ebscohost), and Global Health (Ovid) for HIV-1 subtyping studies published between Jan 1, 1990, and Dec 31, 2015. We collected additional unpublished HIV-1 subtyping data through a global survey. We included prevalence studies with HIV-1 subtyping data collected during 1990-2015. We grouped countries into 14 regions and analysed data for four time periods (1990-99, 2000-04, 2005-09, and 2010-15). The distribution of HIV-1 subtypes, circulating recombinant forms (CRFs), and unique recombinant forms (URFs) in individual countries was weighted according to the UNAIDS estimates of the number of people living with HIV (PLHIV) in each country to generate regional and global estimates of HIV-1 diversity in each time period. The primary outcome was the number of samples designated as HIV-1 subtypes A, B, C, D, F, G, H, J, K, CRFs, and URFs. The systematic review is registered with PROSPERO, number CRD42017067164. FINDINGS: This systematic review and global survey yielded 2203 datasets with 383 519 samples from 116 countries in 1990-2015. Globally, subtype C accounted for 46·6% (16 280 897/34 921 639 of PLHIV) of all HIV-1 infections in 2010-15. Subtype B was responsible for 12·1% (4 235 299/34 921 639) of infections, followed by subtype A (10·3%; 3 587 003/34 921 639), CRF02_AG (7·7%; 2 705 110/34 921 639), CRF01_AE (5·3%; 1 840 982/34 921 639), subtype G (4·6%; 1 591 276/34 921 639), and subtype D (2·7%; 926 255/34 921 639). Subtypes F, H, J, and K combined accounted for 0·9% (311 332/34 921 639) of infections. Other CRFs accounted for 3·7% (1 309 082/34 921 639), bringing the proportion of all CRFs to 16·7% (5 844 113/34 921 639). URFs constituted 6·1% (2 134 405/34 921 639), resulting in recombinants accounting for 22·8% (7 978 517/34 921 639) of all global HIV-1 infections. The distribution of HIV-1 subtypes and recombinants changed over time in countries, regions, and globally. At a global level during 2005-15, subtype B increased, subtypes A and D were stable, and subtypes C and G and CRF02_AG decreased. CRF01_AE, other CRFs, and URFs increased, leading to a consistent increase in the global proportion of recombinants over time. INTERPRETATION: Global and regional HIV diversity is complex and evolving, and is a major challenge to HIV vaccine development. Surveillance of the global molecular epidemiology of HIV-1 remains crucial for the design, testing, and implementation of HIV vaccines. FUNDING: None. ispartof: LANCET INFECTIOUS DISEASES vol:19 issue:2 pages:143-155 ispartof: location:United States status: published