The characterization of the cross-reactive, or heterologous, neutralizing antibody responses developed during human immunodeficiency virus type 1 (HIV-1) infection and the identification of factors associated with their generation are relevant to the development of an HIV vaccine. We report that in healthy HIV-positive, antiretroviral-naïve subjects, the breadth of plasma heterologous neutralizing antibody responses correlates with the time since infection, plasma viremia levels, and the binding avidity of anti-Env antibodies. Anti-CD4-binding site antibodies are responsible for the exceptionally broad cross-neutralizing antibody responses recorded only in rare plasma samples. However, in most cases examined, antibodies to the variable regions and to the CD4-binding site of Env modestly contributed in defining the overall breadth of these responses. Plasmas with broad cross-neutralizing antibody responses were identified that targeted the gp120 subunit, but their precise epitopes mapped outside the variable regions and the CD4-binding site. Finally, although several plasmas were identified with cross-neutralizing antibody responses that were not directed against gp120, only one plasma with a moderate breadth of heterologous neutralizing antibody responses contained cross-reactive neutralizing antibodies against the 4E10 epitope, which is within the gp41 transmembrane subunit. Overall, our study indicates that more than one pathway leads to the development of broad cross-reactive neutralizing antibodies during HIV infection and that the virus continuously escapes their action.

We erroneously indicated (by an asterisk) several clade B isolates as being part of a panel created to evaluate anti-HIV NAb responses during infection or during immunization. The actual viruses that are a part of that panel are: TRO.11, AC10.0.29, PVO.4, QH0692.42, REJO4541.67, SC422661.8, and RHPA4259.7 as shown in the corrected Fig. 1 and 2 on the following pages.

An effective protein based vaccine for tuberculosis (TB) will require a safe and effective adjuvant. There are few adjuvants in approved human vaccines, including Alum and the oil-in-water (o/w) based emulsions MF59 (Novartis Vaccines and Diagnostics), AS03 and AS04 (GlaxoSmith Kline Biologics, GSK) AF03 (Sanofi), and liposomes (Crucell). When used with pure, defined proteins, both Alum and emulsion adjuvants are effective at inducing primarily humoral responses. One of the newest adjuvants in approved products is AS04, which combines monophosphoryl lipid A (MPL), a TLR-4 agonist, with Alum. In this study, we compared two adjuvants, an o/w emulsion (SE), and an o/w emulsion incorporating glucopyranosyl lipid adjuvant (GLA), a synthetic TLR-4 agonist, together with a recombinant protein, ID93. Both the emulsion SE and GLA-SE adjuvants induce potent cellular responses in combination with ID93 in mice. ID93/SE induced Th2 biased immune responses, whereas ID93/GLA-SE induced multifunctional CD4+ Th1 cell responses (IFN-γ, TNF-α and IL-2). The ID93/GLA-SE vaccine candidate induced significant protection in mice and guinea pigs, whereas no protection was observed with ID93/SE, as assessed by reductions in bacterial burden, survival, and pathology. These results highlight the importance of properly formulating subunit vaccines with effective adjuvants for use against TB.

Current vaccine efforts to elicit cross-reactive neutralizing antibodies (NAbs) against human immunodeficiency virus (HIV) focus on the engineering of soluble mimetics of the trimeric HIV Env glycoprotein (commonly termed gp140 immunogens). Such immunogens are thought to be more effective than previously tested monomeric gp120 immunogens at eliciting cross-reactive NAbs. Still, the breadth of neutralizing antibody responses elicited by gp140 immunogens is narrow. Understanding why antibodies elicited by gp140 immunogens fail to neutralize a wide range of heterologous primary HIV isolates is necessary for improving the design of such immunogens. We previously reported that antibodies elicited in macaques by SF162 Env-derived gp140 immunogens fail to neutralize several heterologous "neutralization-resistant" primary HIV type 1 isolates, such as JRFL, ADA, and YU2. Here we show that by replacing the V1 region of Env on these heterologous viruses with that of SF162, we render them highly susceptible to neutralization by the SF162gp140-elicited antibodies. We observed that viral neutralization was mediated not only by vaccineelicited anti-V1 but also by anti-V3 antibodies and antibodies directed against as yet unidentified Env regions, depending on the heterologous Env background. Our study indicates that common neutralization epitopes are differentially exposed on diverse primary HIV isolates and that the V1 loop contributes to this differential exposure. Therefore, the antibody responses elicited by soluble gp140 immunogens will have to overcome several distinct obstacles in order to neutralize diverse primary HIV isolates.The Env glycoprotein (Env) of human immunodeficiency virus (HIV) plays critical roles in several steps of the viral life cycle, including its transmissibility, cellular tropism, and replication kinetics, and it is the target of both cell-mediated and antibody-mediated antiviral immune responses. Env is produced as a single, heavily glycosylated polypeptide that during intracellular processing is cleaved by cellular enzymes into two noncovalently associated subunits: a transmembrane subunit (gp41) and an extracellular subunit (gp120) (14). During processing, the Env oligomerizes into trimers of gp120/gp41 heterodimers (9, 23, 48), and it is this trimeric Env form that allows the viral lipid envelope to fuse with target cell plasma membranes expressing appropriate receptor molecules during the initial steps of infection.Antibodies to almost every Env region have been isolated from infected patients (28). However, not every Env region on the virion-associated trimers is optimally available for antibody binding (5,27,31,35,39). In general, neutralizing antibodies (NAbs) bind to epitopes that are exposed on the virion-associated Env trimer, although NAbs have also been described that preferentially bind to their epitopes once Env attaches itself to cell surface CD4 and undergoes specific conformational changes (29,42,46). Most patients infected with HIV develop NAbs, and many monoclonal antibodies (MA...

Background & Aims Most regions of the world have <3 co-circulating hepatitis B virus (HBV) genotypes, which limits direct comparisons of hepatocellular carcinoma (HCC) risk among HBV-infected persons by genotype. We evaluated HCC incidence by HBV genotype in a cohort of Alaska Native (AN) persons where 5 HBV genotypes (A, B, C, D, F) have been identified. Methods Our cohort comprised AN persons with chronic HBV infection identified during 1983–2012 who consented to participate in the study. Cohort persons were offered annual hepatitis B e antigen (HBeAg) testing and semiannual HCC screening. We developed a logistic regression model to compare HCC risk by genotype, adjusting for age, sex, region, and HBeAg status. Results Among the 1,235 consenting study participants, 711 (57.6%) were male, 510 (41.3%) were HBeAg positive at cohort entry, and 43 (3.5%) developed HCC. The HBV genotype was known for 1,142 (92.5%) persons (13.5% A, 3.9% B, 6.7% C, 56.9% D, 19.0% F). The HCC incidence/1,000 person-years of follow-up for genotypes A, B, C, D, and F was 1.3, 0, 5.5, 0.4, and 4.2, respectively. Compared with persons with HBV genotype B/D infection, the HCC risk was higher for persons with genotypes A (adjusted odds ratio [aOR]: 3.9, 95% CI: 1.14–13.74), C (aOR: 16.3, 95% CI: 5.20–51.11), and F (aOR: 13.9, 95% CI: 5.30–36.69). Conclusion HBV genotype is independently associated with HCC risk. AN persons with genotypes A, C, and F are at higher risk compared with genotypes B or D.

Considerable effort has been directed to develop Mycobacterium tuberculosis (Mtb) vaccines to boost BCG or for those who cannot be immunized with BCG. We hypothesized that CD4+ and CD8+ T cell responses with a heterologous prime/boost vaccine approach could induce long-lived vaccine efficacy against Mtb in C57BL/6 mice. We produced an adenovirus vector expressing ID93 (Ad5-ID93) for induction of CD8 T cells to use with our candidate tuberculosis (TB) vaccine, ID93/GLA-SE, which induces potent Th1 CD4 T cells. Ad5-ID93 generates ID93-specific CD8+ T-cell responses and induces protection against Mtb. When Ad5-ID93 is administered in a prime-boost strategy with ID93/GLA-SE, both CD4+ and CD8+ T cells are generated and provide protection against Mtb. In a MHC class I deficient mouse model, all groups including the Ad5-ID93 group elicited an antigen-specific CD4+ T-cell response and significantly fewer antigen-specific CD8+ T cells, but were still protected against Mtb, suggesting that CD4+ Th1 T cells could compensate for the loss of CD8+ T cells. Lastly, the order of the heterologous immunizations was critical. Long-lived vaccine protection was observed only when Ad5-ID93 was given as the boost following an ID93/GLA-SE prime. The homologous ID93/GLA-SE prime/boost regimen also induced long-lived protection. One of the correlates of protection between these two approaches was an increase in the total number of ID93-specific IFN-γ-producing CD4+ T cells six months following the last immunization. Our findings provide insight into the development of vaccines not only for tuberculosis but other diseases requiring T cell immunity.

HIV-1 gp140 envelope immunogens express conserved epitopes that are targeted by broadly cross-reactive neutralizing antibodies, but they fail to elicit similar antibodies upon immunization. The poor immunogenicity of conserved epitopes on gp140 could be linked to the high immunogenicity of variable Env regions on such constructs. Previous studies have shown that the first hypervariable region (V1 loop) is immunogenic on soluble gp140s but elicits type-specific antibodies. To address issues related to the high immunogenicity of the V1 loop, two conceptually opposite approaches were tested. In the first approach, we eliminated the V1 loop from our gp140 construct and examined how V1 deletion altered the immunogenic properties of other Env regions. In the second approach, we took advantage of the high immunogenicity of the V1 loop and engrafted four diverse V1 loops onto a common gp140 Env "scaffold." These four scaffolds were used as a cocktail of immunogens to elicit diverse anti-V1 antibodies, under the hypothesis that eliciting diverse anti-V1 antibodies would expand the neutralizing breadth of immune sera. Our study indicates that three of four heterologous V1 loops were immunogenic on the common Env backbone "scaffold," but heterologous anti-V1 neutralizing responses were observed in only one case. Both types of V1 modification dampened the immunogenicity of the V3 loop, differentially altered the immunogenicity of the transmembrane gp41 subunit, and altered the relative immunogenicities of unknown Env regions, including potentially the CD4-binding site (CD4-bs) and trimerspecific targets, which elicited cross-reactive neutralizing antibodies but of limited breadth.An effective vaccine against human immunodeficiency virus type 1 (HIV-1) will need to incorporate an envelope-derived immunogen capable of eliciting potent and broadly cross-reactive neutralizing antibody responses against diverse primary HIV-1 isolates. The target of anti-HIV neutralizing antibodies (NAbs), the viral envelope (Env) glycoprotein, is expressed as a single transmembrane polypeptide precursor (gp160) that is glycosylated and cleaved into an extracellular subunit (gp120) and a transmembrane subunit (gp41) during intracellular processing (10,20,21,54). The functional Env form on virion surfaces is a trimer composed of three noncovalently associated gp120-gp41 heterodimers. Soluble forms of the trimeric Env have been generated by introducing stop codons immediately upstream of the transmembrane domain of gp41. These constructs are commonly referred to as gp140 proteins and have been tested extensively as immunogens to elicit anti-HIV-1 NAbs. Soluble gp140s express epitopes that are targets of NAbs, including cross-reactive NAbs such as b12, 4E10, and 2G12 (5,17,34,45,47,49,50,52,57). Immunization with gp140 immunogens nonetheless does not result in a broadly cross-reactive neutralizing antibody response (2,3,17,18,26,56,58).Epitope mapping analyses of the Abs elicited by soluble trimeric gp140 immunogens revealed that a large fraction of...

ObjectiveTo identify recommended components for adopting, implementing and enforcing bans or restrictions targeting flavoured tobacco products.MethodsBetween April and June 2019, semistructured interviews were conducted with 17 high-level experts across the USA and Canada with expertise in flavoured tobacco product policies. Participants included health department staff, researchers, legal professionals and local government officials. Interviews were recorded, transcribed and analysed for key themes.ResultsMajor findings were organised into four categories: programme planning and legislative preparations; education and community outreach; implementation and enforcement; and policy impact. Critical pre-implementation elements included using comprehensive policy language, identifying enforcement agents, examining potential economic costs, deploying media campaigns and engaging community partners and retailers. Recommended implementation processes included a 6-month preparation timeline, focus on retailer education and clearly outlined enforcement procedures, particularly for concept flavours.ConclusionsFlavoured tobacco policies have successfully limited sales, withstood legal challenges and become more comprehensive over time, providing useful lessons to inform ongoing and future legislative and programmatic efforts. Identifying and sharing best practices can improve passage, implementation, efficacy and evaluation of flavoured tobacco policies.