1
|
Patel RS, Agrawal B. Mucosal immunization with lipopeptides derived from conserved regions of SARS-CoV-2 antigens induce robust cellular and cross-variant humoral immune responses in mice. Front Immunol 2023; 14:1178523. [PMID: 37334376 PMCID: PMC10272440 DOI: 10.3389/fimmu.2023.1178523] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/02/2023] [Accepted: 04/17/2023] [Indexed: 06/20/2023] Open
Abstract
Severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2), the causative agent of COVID-19, has infected >600 million people in the ongoing global pandemic. Several variants of the SARS-CoV-2 have emerged in the last >2 years, challenging the continued efficacy of current COVID vaccines. Therefore, there is a crucial need to investigate a highly cross-protective vaccine effective against variants of SARS-CoV-2. In this study, we examined seven lipopeptides derived from highly conserved, immunodominant epitopes from the S, N, and M proteins of SARS-CoV-2, that are predicted to contain epitopes for clinically protective B cells, helper T cells (TH) and cytotoxic T cells (CTL). Intranasal immunization of mice with most of the lipopeptides led to significantly higher splenocyte proliferation and cytokine production, mucosal and systemic antibody responses, and induction of effector B and T lymphocytes in both lungs and spleen, compared to immunizations with the corresponding peptides without lipid. Immunizations with Spike-derived lipopeptides led to cross-reactive IgG, IgM and IgA responses against Alpha, Beta, Delta, and Omicron Spike proteins as well as neutralizing antibodies. These studies support their potential for development as components of a cross-protective SARS-CoV-2 vaccine.
Collapse
|
2
|
Araújo NM, Rubio IGS, Toneto NPA, Morale MG, Tamura RE. The use of adenoviral vectors in gene therapy and vaccine approaches. Genet Mol Biol 2022; 45:e20220079. [PMID: 36206378 PMCID: PMC9543183 DOI: 10.1590/1678-4685-gmb-2022-0079] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/06/2022] [Accepted: 07/12/2022] [Indexed: 11/04/2022] Open
Abstract
Adenovirus was first identified in the 1950s and since then this pathogenic group
of viruses has been explored and transformed into a genetic transfer vehicle.
Modification or deletion of few genes are necessary to transform it into a
conditionally or non-replicative vector, creating a versatile tool capable of
transducing different tissues and inducing high levels of transgene expression.
In the early years of vector development, the application in monogenic diseases
faced several hurdles, including short-term gene expression and even a fatality.
On the other hand, an adenoviral delivery strategy for treatment of cancer was
the first approved gene therapy product. There is an increasing interest in
expressing transgenes with therapeutic potential targeting the cancer hallmarks,
inhibiting metastasis, inducing cancer cell death or modulating the immune
system to attack the tumor cells. Replicative adenovirus as vaccines may be even
older and date to a few years of its discovery, application of non-replicative
adenovirus for vaccination against different microorganisms has been
investigated, but only recently, it demonstrated its full potential being one of
the leading vaccination tools for COVID-19. This is not a new vector nor a new
technology, but the result of decades of careful and intense work in this
field.
Collapse
Affiliation(s)
- Natália Meneses Araújo
- Universidade Federal de São Paulo, Laboratório de Biologia Molecular
do Câncer, São Paulo, SP, Brazil.
| | - Ileana Gabriela Sanchez Rubio
- Universidade Federal de São Paulo, Laboratório de Biologia Molecular
do Câncer, São Paulo, SP, Brazil. ,Universidade Federal de São Paulo, Departamento de Ciências
Biológicas, Diadema, SP, Brazil. ,Universidade Federal de São Paulo, Laboratório de Ciências
Moleculares da Tireóide, Diadema, SP, Brazil.
| | | | - Mirian Galliote Morale
- Universidade Federal de São Paulo, Laboratório de Biologia Molecular
do Câncer, São Paulo, SP, Brazil. ,Universidade Federal de São Paulo, Departamento de Ciências
Biológicas, Diadema, SP, Brazil. ,Universidade Federal de São Paulo, Laboratório de Ciências
Moleculares da Tireóide, Diadema, SP, Brazil.
| | - Rodrigo Esaki Tamura
- Universidade Federal de São Paulo, Laboratório de Biologia Molecular
do Câncer, São Paulo, SP, Brazil. ,Universidade Federal de São Paulo, Departamento de Ciências
Biológicas, Diadema, SP, Brazil.
| |
Collapse
|
3
|
Tarantino G, Citro V, Cataldi M. Findings from Studies Are Congruent with Obesity Having a Viral Origin, but What about Obesity-Related NAFLD? Viruses 2021; 13:1285. [PMID: 34372491 PMCID: PMC8310150 DOI: 10.3390/v13071285] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/29/2021] [Revised: 06/26/2021] [Accepted: 06/26/2021] [Indexed: 02/06/2023] Open
Abstract
Infection has recently started receiving greater attention as an unusual causative/inducing factor of obesity. Indeed, the biological plausibility of infectobesity includes direct roles of some viruses to reprogram host metabolism toward a more lipogenic and adipogenic status. Furthermore, the probability that humans may exchange microbiota components (virome/virobiota) points out that the altered response of IFN and other cytokines, which surfaces as a central mechanism for adipogenesis and obesity-associated immune suppression, is due to the fact that gut microbiota uphold intrinsic IFN signaling. Last but not least, the adaptation of both host immune and metabolic system under persistent viral infections play a central role in these phenomena. We hereby discuss the possible link between adenovirus and obesity-related nonalcoholic fatty liver disease (NAFLD). The mechanisms of adenovirus-36 (Ad-36) involvement in hepatic steatosis/NAFLD consist in reducing leptin gene expression and insulin sensitivity, augmenting glucose uptake, activating the lipogenic and pro-inflammatory pathways in adipose tissue, and increasing the level of macrophage chemoattractant protein-1, all of these ultimately leading to chronic inflammation and altered lipid metabolism. Moreover, by reducing leptin expression and secretion Ad-36 may have in turn an obesogenic effect through increased food intake or decreased energy expenditure via altered fat metabolism. Finally, Ad-36 is involved in upregulation of cAMP, phosphatidylinositol 3-kinase, and p38 signaling pathways, downregulation of Wnt10b expression, increased expression of CCAAT/enhancer binding protein-beta, and peroxisome proliferator-activated receptor gamma 2 with consequential lipid accumulation.
Collapse
Affiliation(s)
- Giovanni Tarantino
- Department of Clinical Medicine and Surgery, “Federico II” University Medical School of Naples, 80131 Napoli, Italy
| | - Vincenzo Citro
- Department of General Medicine, “Umberto I” Hospital, Nocera Inferiore (Sa), 84014 Nocera Inferiore, Italy;
| | - Mauro Cataldi
- Section of Pharmacology, Department of Neuroscience, Reproductive Sciences and Dentistry, “Federico II” University of Naples, 80131 Napoli, Italy;
| |
Collapse
|
4
|
Xiao Y, Xu H, Guo W, Zhao Y, Luo Y, Wang M, He Z, Ding Z, Liu J, Deng L, Sha F, Ma X. Update on treatment and preventive interventions against COVID-19: an overview of potential pharmacological agents and vaccines. MOLECULAR BIOMEDICINE 2020; 1:16. [PMID: 34765999 PMCID: PMC7711057 DOI: 10.1186/s43556-020-00017-w] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/04/2020] [Accepted: 11/11/2020] [Indexed: 02/06/2023] Open
Abstract
The outbreak of coronavirus disease 2019 (COVID-19) triggered by the new member of the coronaviridae family, severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2), has created an unprecedented challenge for global health. In addition to mild to moderate clinical manifestations such as fever, cough, and fatigue, severe cases often developed lethal complications including acute respiratory distress syndrome (ARDS) and acute lung injury. Given the alarming rate of infection and increasing trend of mortality, the development of underlying therapeutic and preventive treatment, as well as the verification of its effectiveness, are the top priorities. Current research mainly referred to and evaluated the application of the empirical treatment based on two precedents, severe acute respiratory syndrome (SARS) and Middle East respiratory syndrome (MERS), including antiviral drugs targeting different stages of virus replication, immunotherapy modulating the overactivated inflammation response, and other therapies such as herbal medicine and mesenchymal stem cells. Besides, the ongoing development of inventing prophylactic interventions such as various vaccines by companies and institutions worldwide is crucial to decline morbidity and mortality. This review mainly focused on promising candidates for the treatment of COVID-19 and collected recently updated evidence relevant to its feasibility in clinical practice in the near future.
Collapse
Affiliation(s)
- Yinan Xiao
- Department of Biotherapy, State Key Laboratory of Biotherapy, West China Hospital, Sichuan University, Chengdu, 610041 China
- West China School of Medicine, West China Hospital, Sichuan University, Chengdu, 610041 China
| | - Hanyue Xu
- West China School of Medicine, West China Hospital, Sichuan University, Chengdu, 610041 China
- West China Hospital, Sichuan University, Chengdu, 610041 China
| | - Wen Guo
- West China School of Medicine, West China Hospital, Sichuan University, Chengdu, 610041 China
- West China Hospital, Sichuan University, Chengdu, 610041 China
| | - Yunuo Zhao
- Department of Biotherapy, State Key Laboratory of Biotherapy, West China Hospital, Sichuan University, Chengdu, 610041 China
- West China Hospital, Sichuan University, Chengdu, 610041 China
| | - Yuling Luo
- Department of Biotherapy, State Key Laboratory of Biotherapy, West China Hospital, Sichuan University, Chengdu, 610041 China
- West China Hospital, Sichuan University, Chengdu, 610041 China
| | - Ming Wang
- Infectious Diseases Center, West China Hospital, Sichuan University, Chengdu, 610041 China
| | - Zhiyao He
- Department of Pharmacy, State Key Laboratory of Biotherapy and Cancer Center, National Clinical Research Center for Geriatrics, West China Hospital, Sichuan University, and Collaborative Innovation Center of Biotherapy, Chengdu, 610041 China
| | - Zhenyu Ding
- Department of Biotherapy, State Key Laboratory of Biotherapy, West China Hospital, Sichuan University, Chengdu, 610041 China
- West China Hospital, Sichuan University, Chengdu, 610041 China
| | - Jiyan Liu
- Department of Biotherapy, State Key Laboratory of Biotherapy, West China Hospital, Sichuan University, Chengdu, 610041 China
- West China Hospital, Sichuan University, Chengdu, 610041 China
| | - Lei Deng
- Jacobi Medical Center, Albert Einstein College of Medicine, Bronx, New York, 10465 USA
| | - Fushen Sha
- Department of Internal Medicine, State University of New York, Downstate Medical Center, Brooklyn, New York, 11203 USA
| | - Xuelei Ma
- Department of Biotherapy, State Key Laboratory of Biotherapy, West China Hospital, Sichuan University, Chengdu, 610041 China
- West China Hospital, Sichuan University, Chengdu, 610041 China
| |
Collapse
|
5
|
Nuovo G, Tili E, Suster D, Matys E, Hupp L, Magro C. Strong homology between SARS-CoV-2 envelope protein and a Mycobacterium sp. antigen allows rapid diagnosis of Mycobacterial infections and may provide specific anti-SARS-CoV-2 immunity via the BCG vaccine. Ann Diagn Pathol 2020; 48:151600. [PMID: 32805515 PMCID: PMC7423587 DOI: 10.1016/j.anndiagpath.2020.151600] [Citation(s) in RCA: 26] [Impact Index Per Article: 6.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/13/2020] [Accepted: 07/13/2020] [Indexed: 01/10/2023]
Abstract
The vaccine BCG has been reported to offer protection against SARS-CoV-2 infection. It has been hypothesized this is based on nonspecific enhancement of innate immunity. This study addressed whether there is strong homology between a SARS-CoV-2 capsid protein and a Mycobacterium bovis protein that would allow for stronger, more specific immune protection. The study also showed the utility of immunohistochemistry in the diagnostic pathology laboratory for elucidating this information. Immunohistochemistry documented that an antibody directed against the SARS-CoV-2 envelope, but not the spike or membrane proteins, strongly cross hybridized to 11/11 Mycobacterial species tested, including M. bovis. BlastP analysis showed high homology of the SARS-CoV-2 envelope protein with 12 consecutive amino acids of the protein LytR C, which is a consensus protein unique to Mycobacteria. Six additional cases of human tuberculosis with few organisms showed that the viral envelope specific antibody (5/6) was more accurate than the AFB stain (2/6) for diagnostic purposes. These data indicate BCG vaccination induces a specific immunity against SARS CoV-2 that targets the viral envelope protein that is essential for infectivity. Thus, a concurrent booster or first use of the BCG vaccine may reduce the severity of the current COVID-19 pandemic. The data also suggests the value of using the SARS-CoV-2 envelope antibody in the diagnosis of Mycobacterial infections in formalin fixed, paraffin embedded tissues by the diagnostic pathologist. The envelope protein of SARS-CoV2 is strongly homologous with a consensus Mycobacterial protein. Immunohistochemistry with an antibody against the viral envelope, thus, can detect Mycobacterial infections. This test is superior to the AFB stain for Mycobacterial detection by the anatomic pathologist. The BCG vaccine offers a strong, viral specific immunity against COVID-19 due to this strong homology.
Collapse
Affiliation(s)
| | - Esmerina Tili
- Department of Anesthesiology and Department of Cancer Biology and Genetics, The Ohio State University Medical Center, Columbus, OH 43210, USA
| | - David Suster
- Department of Pathology, Molecular and Cell-based Medicine, Mount Sinai Hospital and Icahn School of Medicine, NY, NY 10029, USA
| | - Eva Matys
- Discovery Life Sciences, Powell, OH 43065, USA
| | - Lance Hupp
- Discovery Life Sciences, Powell, OH 43065, USA
| | - Cynthia Magro
- Department of Pathology and Laboratory Medicine, NY, NY 10022, USA.
| |
Collapse
|
6
|
Toptygina AP. Heterologous immune responses in health and disease. RUSSIAN JOURNAL OF INFECTION AND IMMUNITY 2020. [DOI: 10.15789/2220-7619-hir-1292] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/01/2022]
Abstract
Immunological memory and tolerance represent major achievements and advantages of adaptive immunity. Organisms bearing adaptive immunity display prominent competitive advantages in the fight against infections. Memory immune cells are preserved for decades and are able to repel a second attack of an infectious agent. However, studies performed in the XXI century have shown that even unrelated pathogens may be quickly and effectively destroyed by memory cells. This type of response is called heterologous so that heterologous immune response is mainly typical to viral infections and other intracellular infections, where T-cells play a lead role in protection. This review will discuss various mechanisms involved in implementing T-cell cross-reactivity, describe molecular prerequisites for heterologous T-cell responses. Experimental evidence of memory T-cell potential to heterologous immune response in mouse models and in human infections are also discussed. Heterologous immune response is an important immune arm in adults and the elderly when the yield of naive cells to the periphery declines due to thymus involution. Along with obvious advantages, heterologous immune response leads to imbalanced memory T-cell repertoire, replacement of immunodominant epitopes with minor ones allowing viruses to evade immune response that results in virus persistence, or, conversely, fulminant infection course. Another threat of heterologous immune response due to switch in dominant repertoire of recognizable epitopes is presented by random self-epitope recognition, which can lead to development of autoimmune pathology. Heterologous immunity can also disrupt drug-induced tolerance in organ and tissue transplants and lead to graft rejection. Heterologous immune response should be taken into consideration while developing and using new vaccines, especially in adults and the elderly.
Collapse
|
7
|
Luo Q, Song H, Deng X, Li J, Jian W, Zhao J, Zheng X, Basnet S, Ge H, Daniel T, Xu B, Fang L. A Triple-Regulated Oncolytic Adenovirus Carrying MicroRNA-143 Exhibits Potent Antitumor Efficacy in Colorectal Cancer. MOLECULAR THERAPY-ONCOLYTICS 2020; 16:219-229. [PMID: 32123722 PMCID: PMC7036723 DOI: 10.1016/j.omto.2020.01.005] [Citation(s) in RCA: 11] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 09/24/2019] [Accepted: 01/13/2020] [Indexed: 12/24/2022]
Abstract
The cancer-targeting gene virotherapy might be a useful strategy for the treatment of cancer, because it could combine the advantages of both gene therapy and virotherapy. This study aimed to construct a triple-regulated oncolytic adenovirus, Ad-RGD-Survivin-ZD55-miR-143, carrying the therapeutic gene miR-143 and evaluate its possible antitumor effect in colorectal cancer. We observed that miR-143 was lowly expressed in patients with colorectal cancer. The upregulation of miR-143 could inhibit cell proliferation and induce cell apoptosis by targeting KRAS in colorectal cancer cells. Then, Ad-RGD-Survivin-ZD55-miR-143 was successfully constructed in this study. Cells infected with Ad-RGD-Survivin-ZD55-miR-143 could inhibit cell proliferation, suppress cell migration and invasion, arrest cells at the G1 phase, and induce cellular apoptosis. At the same time, Ad-RGD-Survivin-ZD55-miR-143 decreased the expression of PARP-1 and KRAS protein in vitro. In a HCT116 xenograft model, intratumoral injection of Ad-RGD-Survivin-ZD55-miR-143 resulted in reduced tumor growth. Furthermore, Ad-RGD-Survivin-ZD55-miR-143 induced apoptosis and decreased the expression level of KRAS in HCT116 xenograft cells. Our results suggested that Ad-RGD-Survivin-ZD55-miR-143 produced a strong antitumor effect by targeting KRAS and that this strategy could broaden the therapeutic options for treating colorectal cancer.
Collapse
Affiliation(s)
- Qifeng Luo
- Department of General Surgery, Shanghai Tenth People's Hospital, Tongji University School of Medicine, Shanghai 200072, P. R. China
| | - Hongming Song
- Department of General Surgery, Shanghai Tenth People's Hospital, Tongji University School of Medicine, Shanghai 200072, P. R. China.,Breast Disease Center, The Affiliated Hospital of Qingdao University, Shandong 266000, P. R. China
| | - Xiaochong Deng
- Department of General Surgery, Shanghai Tenth People's Hospital, Tongji University School of Medicine, Shanghai 200072, P. R. China
| | - Jiayi Li
- Department of General Surgery, Shanghai Tenth People's Hospital, Tongji University School of Medicine, Shanghai 200072, P. R. China
| | - Wei Jian
- Department of General Surgery, Shanghai Tenth People's Hospital, Tongji University School of Medicine, Shanghai 200072, P. R. China
| | - Junyong Zhao
- Department of General Surgery, Shanghai Tenth People's Hospital, Tongji University School of Medicine, Shanghai 200072, P. R. China
| | - Xueyu Zheng
- Department of General Surgery, Shanghai Tenth People's Hospital, Tongji University School of Medicine, Shanghai 200072, P. R. China
| | - Shiva Basnet
- Department of Gastrointestinal Surgery, Shanghai East Hospital, Tongji University School of Medicine, Shanghai 200120, P. R. China
| | - Haiyan Ge
- Department of Gastrointestinal Surgery, Shanghai East Hospital, Tongji University School of Medicine, Shanghai 200120, P. R. China
| | - Twingle Daniel
- Centre for Cancer Research, The Westmead Institute for Medical Research, The University of Sydney, Westmead, NSW 2145, Australia
| | - Bin Xu
- Department of General Surgery, Shanghai Tenth People's Hospital, Tongji University School of Medicine, Shanghai 200072, P. R. China
| | - Lin Fang
- Department of General Surgery, Shanghai Tenth People's Hospital, Tongji University School of Medicine, Shanghai 200072, P. R. China
| |
Collapse
|
8
|
Agrawal B. Heterologous Immunity: Role in Natural and Vaccine-Induced Resistance to Infections. Front Immunol 2019; 10:2631. [PMID: 31781118 PMCID: PMC6856678 DOI: 10.3389/fimmu.2019.02631] [Citation(s) in RCA: 61] [Impact Index Per Article: 12.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/25/2019] [Accepted: 10/23/2019] [Indexed: 12/11/2022] Open
Abstract
The central paradigm of vaccination is to generate resistance to infection by a specific pathogen when the vacinee is re-exposed to that pathogen. This paradigm is based on two fundamental characteristics of the adaptive immune system, specificity and memory. These characteristics come from the clonal specificity of T and B cells and the long-term survival of previously-encountered memory cells which can rapidly and specifically expand upon re-exposure to the same specific antigen. However, there is an increasing awareness of the concept, as well as experimental documentation of, heterologous immunity and cross-reactivity of adaptive immune lymphocytes in protection from infection. This awareness is supported by a number of human epidemiological studies in vaccine recipients and/or individuals naturally-resistant to certain infections, as well as studies in mouse models of infections, and indeed theoretical considerations regarding the disproportional repertoire of available T and B cell clonotypes compared to antigenic epitopes found on pathogens. Heterologous immunity can broaden the protective outcomes of vaccinations, and natural resistance to infections. Besides exogenous microbes/pathogens and/or vaccines, endogenous microbiota can also impact the outcomes of an infection and/or vaccination through heterologous immunity. Moreover, utilization of viral and/or bacterial vaccine vectors, capable of inducing heterologous immunity may also influence the natural course of many infections/diseases. This review article will briefly discuss these implications and redress the central dogma of specificity in the immune system.
Collapse
Affiliation(s)
- Babita Agrawal
- Department of Surgery, Faculty of Medicine and Dentistry, University of Alberta, Edmonton, AB, Canada
| |
Collapse
|
9
|
Antibodies to Cryptic Epitopes in Distant Homologues Underpin a Mechanism of Heterologous Immunity between Plasmodium vivax PvDBP and Plasmodium falciparum VAR2CSA. mBio 2019; 10:mBio.02343-19. [PMID: 31594821 PMCID: PMC6786876 DOI: 10.1128/mbio.02343-19] [Citation(s) in RCA: 12] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/08/2023] Open
Abstract
In this work, we describe a molecular mechanism of heterologous immunity between two distant species of Plasmodium. Our results suggest a mechanism that subverts the classic parasite strategy of presenting highly polymorphic epitopes in surface antigens to evade immunity to that parasite. This alternative immune pathway can be exploited to protect pregnant women from falciparum placental malaria by designing vaccines to cryptic epitopes that elicit broadly inhibitory antibodies against variant parasite strains. Many pathogens evolve extensive genetic variation in virulence proteins as a strategy to evade host immunity. This poses a significant challenge for the host to develop broadly neutralizing antibodies. In Plasmodium falciparum, we show that a mechanism to circumvent this challenge is to elicit antibodies to cryptic epitopes that are not under immune pressure. We previously discovered that antibodies to the Plasmodium vivax invasion protein, PvDBP, cross-react with P. falciparum VAR2CSA, a distantly related virulence factor that mediates placental malaria. Here, we describe the molecular mechanism underlying this cross-species immunity. We identified an epitope in subdomain 1 (SD1) within the Duffy binding-like (DBL) domain of PvDBP that gives rise to cross-reactive antibodies to VAR2CSA and show that human antibodies affinity purified against a synthetic SD1 peptide block parasite adhesion to chondroitin sulfate A (CSA) in vitro. The epitope in SD1 is subdominant and highly conserved in PvDBP, and in turn, SD1 antibodies target cryptic epitopes in P. falciparum VAR2CSA. The epitopes in VAR2CSA recognized by vivax-derived SD1 antibodies (of human and mouse origin) are distinct from those recognized by VAR2CSA immune serum. We mapped two peptides in the DBL5ε domain of VAR2CSA that are recognized by SD1 antibodies. Both peptides map to regions outside the immunodominant sites, and antibodies to these peptides are not elicited following immunization with VAR2CSA or natural infection with P. falciparum in pregnancy, consistent with the cryptic nature of these target epitopes.
Collapse
|