Cross-protective characteristics of specific immune response induced by HSV-1 attenuated strain M3 against HSV-2 infection / 中华微生物学和免疫学杂志

Objective:To analyze the characteristics of immune cross-reaction between herpes simplex virus type 1 (HSV-1) and HSV-2 in terms of serology and clinical protection aiming to provide data for the control and prevention of diseases caused by the two viruses.Methods:An attenuated HSV-1 strain M3 was used to immunize BALB/c mice. Specific immune responses indicated by the production of neutralizing antibodies were detected. Wild-type HSV-1 and HSV-2 strains were respectively used to infect the mice through different ways 28 d after the immunization to observe the protective immunity in the M3-immunized mice against HSV-1/2 infection.Results:M3 strain could not induce specific neutralizing antibodies against HSV-2. Therefore, viral loads in tissues of the immunized mice increased significantly following different modes of HSV-2 exposure. However, no obvious abnormal clinical manifestations were found and the histopathological damage was only slight inflammatory reaction. In contrast, HSV-1-specific neutralizing antibodies were elicited in the M3-immunizaed mice with significant protective effects against HSV-1 infection.Conclusions:The immune response induced by attenuated HSV-1 strain M3 in mice exhibited immune-protective effects characterized by production of neutralizing antibodies and inhibition of virus proliferation in vivo against wild-type HSV-1 infection. For HSV-2, instead of neutralizing virus in form of antibodies, it featured by more of clinical cross-immunoprotective abilities to control virus growth.

An in-depth investigation of the safety and immunogenicity of an inactivated SARS-CoV-2 vaccine

BACKGROUNDIn-depth investigations of the safety and immunogenicity of inactivated SARS-CoV-2 vaccines are needed. METHODIn a phase I randomized, double-blinded, and placebo-controlled trial involving 192 healthy adults 18-59 years of age, two injections of three different doses (50 EU, 100 EU and 150 EU) of an inactivated SARS-CoV-2 vaccine or the placebo were administered intramuscularly with a 2- or 4-week interval between the injections. The safety and immunogenicity of the vaccine were evaluated within 28 days. FINDINGIn this study, 191 subjects assigned to three doses groups or the placebo group completed the 28-day trial. There were 44 adverse reactions within the 28 days, most commonly mild pain and redness at the injection site or slight fatigue, and no abnormal variations were observed in 48 cytokines in the serum samples of immunized subjects. The serum samples diluted from 1:32 to 1:4096 and incubated with the virus did not show antibody-dependent enhancement effects (ADEs) with regard to human natural killer cells, macrophages or dendritic cells. At day 14, the seroconversion rates had reached 92%, 100% and 96% with geometric mean titers (GMTs) of 18.0, 54.5 and 37.1, and at day 28, the seroconversion rates had reached 80%, 96% and 92% with GMTs of 10.6, 15.4 and 19.6in 0, 14 and 0, 28 procedures, respectively. Seroconversion was associated with the synchronous upregulation of ELISA antibodies against the S protein, N protein and virion and a cytotoxic T lymphocyte (CTL) response. Transcriptome analysis shaped the genetic diversity of immune response induced by the vaccine. INTERPRETATIONIn a population aged 18-59 years, this inactivated SARS-CoV-2 vaccine was safe and immunogenic. Trial registrationNCT04412538 FUNDINGThe National Key R&D Program of China (2020YFC0849700), the Program of Chinese Academy of Medicine Science and the Major Science and Technology Special Projects of Yunnan Province.

A valid protective immune response elicited in rhesus macaques by an inactivated vaccine is capable of defending against SARS-CoV-2 infection

With the relatively serious global epidemic outbreak of SARS-CoV-2 infection, public concerns focus on not only clinical therapeutic measures and public quarantine for this disease but also the development of vaccines. The technical design of our SARS-CoV-2 inactivated vaccine provides a viral antigen that enables the exposure of more than one structural protein based upon the antibody composition of COVID-19 patients convalescent serum. This design led to valid immunity with increasing neutralizing antibody titers and a CTL response detected post-immunization of this vaccine by two injections in rhesus macaques. Further, this elicited immunoprotection in macaques enables not only to restrain completely viral replication in tissues of immunized animals, compared to the adjuvant control and those immunized by an RBD peptide vaccine, but also to significantly alleviate inflammatory lesion in lung tissues in histo-pathologic detection, compared to the adjuvant control with developed interstitial pneumonia. The data obtained from these macaques immunized with the inactivated vaccine or RBD peptide vaccine suggest that immunity with a clinically protective effect against SARS-CoV-2 infection should include not only specific neutralizing antibodies but also specific CTL responses against at least the S and N antigens.

Molecular characterization of immune response signaling molecules induced by transfection of cox-sackievirus B2 structural proteins into epithelial cells / 中华微生物学和免疫学杂志

Objective To investigate the molecular characteristics of immune response signaling molecules induced by transfection of coxsackievirus B2 ( CVB2 ) structural proteins into epithelial cells. Methods Recombinant eukaryotic expression plasmids containing the coding regions of CVB2 structural proteins VP1-VP4 were constructed and then transfected into 16HBE cells. Culture supernatants and cell ly-sates of the transfected 16HBE cells were collected. Expression of signaling molecules involved in innate im-mune responses in transfected 16HBE cells at mRNA level was detected by RT-Q-PCR. The proliferation of T cells co-cultured with culture supernatants and cell lysates of the transfected 16HBE cells was analyzed by ELISPOT. Results Expression of innate immunity-related signaling molecules such as TGF-β-activated ki-nase ( TAK) , NF-κB-inducing kinase ( NIK) , IκB kinase α ( IKKα) and IFN-β at mRNA level was up-regulated in 16HBE cells transfected with CVB2 structural proteins VP1-VP4. Both culture supernatants and cell lysates of the transfected 16HBE cells enhanced the proliferation of T cells. Conclusions CVB2 struc-tural proteins VP1-VP4 could enhance the expression of innate immunity-related signaling molecules to var-ying degrees and promote the activation of adaptive immunity.