Mt10-CVB3 Vaccine Virus Protects against CVB4 Infection by Inducing Cross-Reactive, Antigen-Specific Immune Responses

Abstract

Group B coxsackieviruses (CVB) containing six serotypes, B1–B6, affect various organs, and multiple serotypes can induce similar diseases such as myocarditis and pancreatitis. Yet, no vaccines are currently available to prevent these infections. Translationally, the derivation of vaccines that offer protection against multiple serotypes is highly desired. In that direction, we recently reported the generation of an attenuated strain of CVB3, termed Mt10, which completely protects against both myocarditis and pancreatitis induced by the homologous wild-type CVB3 strain. Here, we report that the Mt10 vaccine can induce cross-protection against multiple CVB serotypes as demonstrated with CVB4. We note that the Mt10 vaccine could induce cross-reactive neutralizing antibodies (nABs) against both CVB1 and CVB4. In challenge studies with CVB4, the efficacy of the Mt10 vaccine was found to be 92%, as determined by histological evaluation of the heart and pancreas. Antibody responses induced in Mt10/CVB4 challenged animals indicated the persistence of cross-reactive nABs against CVB1, CVB3, and CVB4. Evaluation of antigen-specific immune responses revealed viral protein 1 (VP1)-reactive antibodies, predominantly IgG2a, IgG2b, IgG3, and IgG1. Similarly, by using major histocompatibility complex class II tetramers, we noted induction of VP1-specific CD4 T cells capable of producing multiple T cell cytokines, with interferon-γ being predominant. Finally, none of the vaccine recipients challenged with CVB4 revealed the presence of viral nucleic acid in the heart or pancreas. Taken together, our data suggest that the Mt10 vaccine can prevent infections caused by multiple CVB serotypes, paving the way for the development of monovalent CVB vaccines to prevent heart and pancreatic diseases of enteroviral origin.

A Monovalent Mt10-CVB3 Vaccine Prevents CVB4-Accelerated Type 1 Diabetes in NOD Mice

“…We recently reported the creation of a novel live-attenuated CVB3 vaccine candidate, Mt10, that offers protection against both homologous (CVB3) and heterologous (CVB4) serotypes of CVB [ 32 , 33 ]. CVBs affect various organ systems [ 19 , 20 , 21 ], and although similar diseases are induced by multiple serotypes, their disease severities may vary in susceptible mouse strains such as A/J, BALB/c, or NOD mice [ 41 , 42 , 43 ].…”

“…Mt10 vaccine virus, CVB1-conn5, CVB3 Nancy, and CVB4-E2 were propagated and titrated as described previously [ 32 , 33 ]. In brief, LLC-MK2 cells or Vero cells (ATCC, Manassas, VA, USA) were grown to ~90% confluency.…”

“…A virus neutralization test was performed using the sera obtained from different groups as described previously [ 32 , 33 ]. In brief, LLC-MK2 cells (for CVB1) or Vero cells (for CVB3 and CVB4) were plated at 0.25 × 10 6 cells/mL in 96-well plates to obtain 90–100% confluency.…”

“…To that end, we made efforts to develop vaccines for CVBs and identified one live-attenuated CVB3 vaccine strain, designated mutant (Mt)10, which can prevent infections caused by homologous (CVB3) and heterologous (CVB4) strains [ 32 , 33 ]. As described elsewhere, the Mt10 virus vaccine prevented both myocarditis and pancreatitis by inducing neutralizing antibodies (nAbs) and antigen-specific T cell responses in challenge studies [ 32 , 33 ]. By extending these observations, we report here that the Mt10 vaccine virus could prevent CVB4-accelerated T1D in the non-obese diabetic (NOD) mice by inducing cross-reactive nAbs.…”

PhIP-Seq Reveals Autoantibodies for Ubiquitously Expressed Antigens in Viral Myocarditis

“…CVB3 (human isolate, Nancy strain) and CVB4-E2 were grown in Vero cells and titered as previously described [ 20 , 21 ]. Virus stocks were diluted in 1× PBS, and virus inocula were administered intraperitoneally (i.p) to A/J mice at doses of 10,000 TCID 50 /200 µL of CVB3 and 2000 TCID 50 /200 µL of CVB4.…”