Assessment of an LSDV-Vectored Vaccine for Heterologous Prime-Boost Immunizations against HIV

AbstractA small number of HIV-1 infected individuals develop broadly neutralizing-antibodies to the virus (bNAbs). These antibodies are protective against infection in animal models. However, they only emerge 1 - 3 years after infection, and show a number of highly unusual features including exceedingly high levels of somatic mutations. It is therefore not surprising that elicitation of protective immunity to HIV-1 has not yet been possible. Here we show that mature, primary mouse and human B cells can be editedin vitrousing CRISPR/Cas9 to express mature bNAbs from the endogenousIghlocus. Moreover, edited B cells retain the ability to participate in humoral immune responses. Immunization with cognate antigen in wild type mouse recipients of edited B cells elicits bNAb titers that neutralize HIV-1 at levels associated with protection against infection. This approach enables humoral immune responses that may be difficult to elicit by traditional immunization.One-sentence summaryB cells edited by CRISPR/Cas9 to produce antibodies participate in humoral immune reactions and secrete neutralizing serum titers of anti-HIV bNAbs.

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HIV-specific humoral immune responses by CRISPR/Cas9-edited B cells

Journal of Experimental Medicine ◽

10.1084/jem.20190287 ◽

2019 ◽

Vol 216 (6) ◽

pp. 1301-1310 ◽

Cited By ~ 19

Author(s):

Harald Hartweger ◽

Andrew T. McGuire ◽

Marcel Horning ◽

Justin J. Taylor ◽

Pia Dosenovic ◽

...

Keyword(s):

B Cells ◽

Immune Responses ◽

Neutralizing Antibodies ◽

Wild Type Mouse ◽

Humoral Immune ◽

Humoral Immune Responses ◽

Human B Cells ◽

Primary Mouse ◽

Hiv 1

A small number of HIV-1–infected individuals develop broadly neutralizing antibodies to the virus (bNAbs). These antibodies are protective against infection in animal models. However, they only emerge 1–3 yr after infection, and show a number of highly unusual features including exceedingly high levels of somatic mutations. It is therefore not surprising that elicitation of protective immunity to HIV-1 has not yet been possible. Here we show that mature, primary mouse and human B cells can be edited in vitro using CRISPR/Cas9 to express mature bNAbs from the endogenous Igh locus. Moreover, edited B cells retain the ability to participate in humoral immune responses. Immunization with cognate antigen in wild-type mouse recipients of edited B cells elicits bNAb titers that neutralize HIV-1 at levels associated with protection against infection. This approach enables humoral immune responses that may be difficult to elicit by traditional immunization.

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HIV-1 Envelope Glycosylation and the Signal Peptide

10.20944/preprints202102.0210.v1 ◽

2021 ◽

Author(s):

Gregory S. Lambert ◽

Chitra Upadhyay

Keyword(s):

Signal Peptide ◽

Neutralizing Antibodies ◽

Vaccine Trial ◽

Vaccine Design ◽

Antibody Responses ◽

Broadly Neutralizing Antibodies ◽

Structural Determinants ◽

Humoral Immune ◽

Env Protein ◽

Hiv 1

The RV144 trial represents the only vaccine trial to demonstrate any protective effect against HIV-1 infection. While the reason(s) for this protection are still being evaluated, it serves as justification for widespread efforts aimed at developing new, more effective HIV-1 vaccines. Advances in our knowledge of HIV-1 immunogens and host antibody responses to these immunogens are crucial to informing vaccine design. While the envelope (Env) protein is the only viral protein present on the surface of virions, it exists in a complex trimeric conformation and is decorated with an array of variable N-linked glycans, making it an important but difficult target for vaccine design. Thus far, efforts to elicit a protective humoral immune response using structural mimics of native Env trimers have been unsuccessful. Notably, the aforementioned N-linked glycans serve as a component of many of the epitopes crucial for the induction of potentially protective broadly neutralizing antibodies (bnAbs). Thus, a greater understanding of Env structural determinants, most critically Env glycosylation, will no doubt be of importance in generating effective immunogens. Recent studies have identified the HIV-1 Env signal peptide (SP) as an important contributor to Env glycosylation. Further investigation into the mechanisms by which the SP directs glycosylation will be important, both in the context of understanding HIV-1 biology and in order to inform HIV-1 vaccine design.

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Monophosphoryl-Lipid A (MPLA) is an Efficacious Adjuvant for Inactivated Rabies Vaccines

Viruses ◽

10.3390/v11121118 ◽

2019 ◽

Vol 11 (12) ◽

pp. 1118 ◽

Cited By ~ 1

Author(s):

Chen Chen ◽

Chengguang Zhang ◽

Ruiming Li ◽

Zongmei Wang ◽

Yueming Yuan ◽

...

Keyword(s):

Immune Responses ◽

Neutralizing Antibodies ◽

Lipid A ◽

Survival Ratio ◽

Effective Measure ◽

Humoral Immune ◽

Humoral Immune Responses ◽

Monophosphoryl Lipid A ◽

Monophosphoryl Lipid

Rabies, as one of the most threatening zoonoses in the world, causes a fatal central nervous system (CNS) disease. So far, vaccination with rabies vaccines has been the most effective measure to prevent and control this disease. At present, inactivated rabies vaccines are widely used in humans and domestic animals. However, humoral immune responses induced by inactivated rabies vaccines are relatively low and multiple shots are required to achieve protective immunity. Supplementation with an adjuvant is a practical way to improve the immunogenicity of inactivated rabies vaccines. In this study, we found that monophosphoryl-lipid A (MPLA), a well-known TLR4 agonist, could significantly promote the maturation of bone marrow-derived dendritic cells (BMDC) through a TLR4-dependent pathway in vitro and the maturation of conventional DCs (cDCs) in vivo. We also found that MPLA, serving as an adjuvant for inactivated rabies vaccines, could significantly facilitate the generation of T follicular helper (Tfh) cells, germinal center (GC) B cells, and plasma cells (PCs), consequently enhancing the production of RABV-specific total-IgG, IgG2a, IgG2b, and the virus-neutralizing antibodies (VNAs). Furthermore, MPLA could increase the survival ratio of mice challenged with virulent RABV. In conclusion, our results demonstrate that MPLA serving as an adjuvant enhances the intensity of humoral immune responses by activating the cDC–Tfh–GC B axis. Our findings will contribute to the improvement of the efficiency of traditional rabies vaccines.

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HIV-1 Envelope Glycosylation and the Signal Peptide

Vaccines ◽

10.3390/vaccines9020176 ◽

2021 ◽

Vol 9 (2) ◽

pp. 176

Author(s):

Gregory S. Lambert ◽

Chitra Upadhyay

Keyword(s):

Signal Peptide ◽

Neutralizing Antibodies ◽

Vaccine Trial ◽

Vaccine Design ◽

Antibody Responses ◽

Broadly Neutralizing Antibodies ◽

Structural Determinants ◽

Humoral Immune ◽

Env Protein ◽

Hiv 1

The RV144 trial represents the only vaccine trial to demonstrate any protective effect against HIV-1 infection. While the reason(s) for this protection are still being evaluated, it serves as justification for widespread efforts aimed at developing new, more effective HIV-1 vaccines. Advances in our knowledge of HIV-1 immunogens and host antibody responses to these immunogens are crucial to informing vaccine design. While the envelope (Env) protein is the only viral protein present on the surface of virions, it exists in a complex trimeric conformation and is decorated with an array of variable N-linked glycans, making it an important but difficult target for vaccine design. Thus far, efforts to elicit a protective humoral immune response using structural mimics of native Env trimers have been unsuccessful. Notably, the aforementioned N-linked glycans serve as a component of many of the epitopes crucial for the induction of potentially protective broadly neutralizing antibodies (bnAbs). Thus, a greater understanding of Env structural determinants, most critically Env glycosylation, will no doubt be of importance in generating effective immunogens. Recent studies have identified the HIV-1 Env signal peptide (SP) as an important contributor to Env glycosylation. Further investigation into the mechanisms by which the SP directs glycosylation will be important, both in the context of understanding HIV-1 biology and in order to inform HIV-1 vaccine design.

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HIV-1 Tat-coated nanoparticles result in enhanced humoral immune responses and neutralizing antibodies compared to alum adjuvant

Vaccine ◽

10.1016/j.vaccine.2006.01.065 ◽

2006 ◽

Vol 24 (17) ◽

pp. 3564-3573 ◽

Cited By ~ 23

Author(s):

J PATEL ◽

D GALEY ◽

J JONES ◽

P RAY ◽

J WOODWARD ◽

...

Keyword(s):

Immune Responses ◽

Neutralizing Antibodies ◽

Humoral Immune ◽

Humoral Immune Responses ◽

Coated Nanoparticles ◽

Hiv 1

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Non-neutralizing antibodies targeting the immunogenic regions of HIV-1 envelope reduce mucosal infection and virus burden in humanized mice

PLoS Pathogens ◽

10.1371/journal.ppat.1010183 ◽

2022 ◽

Vol 18 (1) ◽

pp. e1010183

Author(s):

Catarina E. Hioe ◽

Guangming Li ◽

Xiaomei Liu ◽

Ourania Tsahouridis ◽

Xiuting He ◽

...

Keyword(s):

Neutralizing Antibodies ◽

Vaccine Trial ◽

Microbial Pathogens ◽

Humanized Mice ◽

Tier 2 ◽

Human Mabs ◽

Hematopoietic Stem ◽

Neutralizing Activity ◽

Hiv 1

Antibodies are principal immune components elicited by vaccines to induce protection from microbial pathogens. In the Thai RV144 HIV-1 vaccine trial, vaccine efficacy was 31% and the sole primary correlate of reduced risk was shown to be vigorous antibody response targeting the V1V2 region of HIV-1 envelope. Antibodies against V3 also were inversely correlated with infection risk in subsets of vaccinees. Antibodies recognizing these regions, however, do not exhibit potent neutralizing activity. Therefore, we examined the antiviral potential of poorly neutralizing monoclonal antibodies (mAbs) against immunodominant V1V2 and V3 sites by passive administration of human mAbs to humanized mice engrafted with CD34+ hematopoietic stem cells, followed by mucosal challenge with an HIV-1 infectious molecular clone expressing the envelope of a tier 2 resistant HIV-1 strain. Treatment with anti-V1V2 mAb 2158 or anti-V3 mAb 2219 did not prevent infection, but V3 mAb 2219 displayed a superior potency compared to V1V2 mAb 2158 in reducing virus burden. While these mAbs had no or weak neutralizing activity and elicited undetectable levels of antibody-dependent cellular cytotoxicity (ADCC), V3 mAb 2219 displayed a greater capacity to bind virus- and cell-associated HIV-1 envelope and to mediate antibody-dependent cellular phagocytosis (ADCP) and C1q complement binding as compared to V1V2 mAb 2158. Mutations in the Fc region of 2219 diminished these effector activities in vitro and lessened virus control in humanized mice. These results demonstrate the importance of Fc functions other than ADCC for antibodies without potent neutralizing activity.

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Antibodies from rabbits immunized with HIV-1 clade B SOSIP trimers can neutralize multiple clade B viruses by destabilizing the envelope glycoprotein

Journal of Virology ◽

10.1128/jvi.00094-21 ◽

2021 ◽

Author(s):

M. M. van Haaren ◽

L. E. McCoy ◽

J. L. Torres ◽

W Lee ◽

C. A. Cottrell ◽

...

Keyword(s):

Immune Responses ◽

Envelope Glycoprotein ◽

Neutralizing Antibodies ◽

Humoral Immune ◽

Humoral Immune Responses ◽

Immunization Strategies ◽

Clade B ◽

Humoral Responses ◽

Neutralization Ability ◽

Hiv 1

The high HIV-1 viral diversity is a formidable hurdle for the development of an HIV-1 vaccine. Elicitation of broadly neutralizing antibodies (bNAbs) would offer a solution, but so far immunization strategies have failed to elicit bNAbs efficiently. To overcome the obstacles, it is important to understand the immune responses elicited by current HIV-1 envelope glycoprotein (Env) immunogens. To gain more insight, we characterized monoclonal antibodies (mAbs) isolated from rabbits immunized with Env SOSIP trimers based on the clade B isolate AMC008. Four rabbits that were immunized three times with AMC008 trimer developed robust autologous and sporadic low-titer heterologous neutralizing responses. Seventeen AMC008 trimer-reactive mAbs were isolated using antigen-specific single B cell sorting. Four of these mAbs neutralized the autologous AMC008 virus and several other clade B viruses. When visualized by electron microscopy, the complex of the neutralizing mAbs with the AMC008 trimer showed binding to the gp41 subunit with unusual approach angles and we observed that their neutralization ability depended on their capacity to induce Env trimer dissociation. Thus, AMC008 SOSIP trimer immunization induced clade B neutralizing mAbs with unusual approach angles with neutralizing effects that involve trimer destabilization. Optimizing these responses might provide an avenue to the induction of trimer dissociating bNAbs. IMPORTANCE Roughly 32 million people have died as a consequence of HIV-1 infection since the start of the epidemic and still 1.7 million people get infected with HIV-1 annually. Therefore, a vaccine to prevent HIV-1 infection is urgently needed. Current HIV-1 immunogens are not able to elicit the broad immune responses needed to provide protection against the large variation of HIV-1 strains circulating globally. A better understanding of the humoral immune responses elicited by immunization with state-of-the-art HIV-1 immunogens should facilitate the design of improved HIV-1 vaccine candidates. We identified antibodies with the ability to neutralize multiple HIV-1 viruses by destabilization of the envelope glycoprotein. Their weak but consistent cross-neutralization ability indicates the potential of this epitope to elicit broad responses. The trimer-destabilizing effect of the neutralizing mAbs combined with detailed characterization of the neutralization epitope can be used to shape the next generation of HIV-1 immunogens to elicit improved humoral responses after vaccination.

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