Two long-lasting human monoclonal antibodies cross-react with monkeypox virus A35 antigen

Monkeypox: A comprehensive review on mutation, transmission, pathophysiology, and therapeutics

Monkeypox virus (MPXV) is the causative agent of the monkeypox (Mpox) disease, belongs to the Orthopoxvirus genus of the Poxviridae family. Due to the recent re-emergence of Mpox in 2024, this is the second time when the World Health Organization (WHO) declared Mpox as a Public Health Emergency of International Concern (PHEIC). This review intends to offer an in-depth analysis of Mpox, including its key characteristics, epidemiological, mutation, pathophysiology, transmission, and therapeutics. The infection of MPXV is a lethal threat to children, pregnant women, and immunocompromised individuals. However, we can prevent the infection by proper precautions including hygiene practices and minimizing exposure to infected individuals or animals. Multivalent mRNA vaccines, antibody-based immunotherapy, and combination drug therapies have all shown significant effectiveness in treating Mpox infection. In addition to addressing antivirals and drug resistance, the review also explores potential targets for vaccine and drug development, as well as the use of animal models for studying MPXV. Because of multiple mutational events, Mpox began exhibiting drug resistance. Overall, this review will contribute significantly to advancing the development of new vaccines and drug options for combating emerging Mpox.

Experimental inoculation of pigs with monkeypox virus results in productive infection and transmission to sentinels

Monkeypox virus (MPXV) is a re-emerging zoonotic poxvirus responsible for producing skin lesions in humans. Endemic in sub-Saharan Africa, the 2022 outbreak with a clade IIb strain has resulted in ongoing sustained transmission of the virus worldwide. MPXV has a relatively wide host range, with infections reported in rodent and non-human primate species. However, the susceptibility of many domestic livestock species remains unknown. Here, we report on a susceptibility/transmission study in domestic pigs that were experimentally inoculated with a 2022 MPXV clade IIb isolate or served as sentinel contact control animals. Several principal-infected and sentinel contact control pigs developed minor lesions near the lips and nose starting at 12 through 18 days post-challenge (DPC). No virus was isolated and no viral DNA was detected from the lesions; however, MPXV antigen was detected by IHC in tissue from a pustule of a principal infected pig. Viral DNA and infectious virus were detected in nasal and oral swabs up to 14 DPC, with peak titers observed at 7 DPC. Viral DNA was also detected in nasal tissues or skin collected from two principal-infected animals at 7 DPC post-mortem. Furthermore, all principal-infected and sentinel control animals enrolled in the study seroconverted. In conclusion, we provide the first evidence that domestic pigs are susceptible to experimental MPXV infection and can transmit the virus to contact animals.

Levels of antibodies against the monkeypox virus compared by HIV status and historical smallpox vaccinations: a serological study

Men who have sex with men and people living with HIV are disproportionately affected in the 2022 multi-country monkeypox epidemic. The smallpox vaccine can induce cross-reactive antibodies against the monkeypox virus (MPXV) and reduce the risk of infection. Data on antibodies against MPXV induced by historic smallpox vaccination in people with HIV are scarce. In this observational study, plasma samples were collected from people living with and without HIV in Shenzhen, China. We measured antibodies binding to two representative proteins of vaccinia virus (VACV; A27L and A33R) and homologous proteins of MPXV (A29L and A35R) using an enzyme-linked immunosorbent assay. We compared the levels of these antibodies between people living with and without HIV. Stratified analyses were performed based on the year of birth of 1981 when the smallpox vaccination was stopped in China. Plasma samples from 677 people living with HIV and 746 people without HIV were tested. A consistent pattern was identified among the four antibodies, regardless of HIV status. VACV antigen-reactive and MPXV antigen-reactive antibodies induced by historic smallpox vaccination were detectable in the people born before 1981, and antibody levels reached a nadir during or after 1981. The levels of smallpox vaccine-induced antibodies were comparable between people living with HIV and those without HIV. Our findings suggest that the antibody levels against MPXV decreased in both people living with and without HIV due to the cessation of smallpox vaccination.

Identification of neutralizing antibodies against monkeypox virus using high-throughput sequencing of A35+H3L+B cells from patients with convalescent monkeypox

The global monkeypox virus (MPXV) outbreak in 2022 emphasizes the urgent need for effective and accessible new-generation vaccines and neutralizing antibodies. Herein, we identified MPXV-neutralizing antibodies using high-throughput single-cell RNA and V(D)J sequencing of antigen-sorted B cells from patients with convalescent monkeypox. IgG1-expressing B cells were obtained from 34 paired heavy- and light-chain B cell receptor sequences. Subsequently, three potent neutralizing antibodies, MV127, MV128, and MV129, were identified and reacted with the MPXV A35 protein. Among these, MV129, which has a half-maximal inhibitory concentration of 2.68μg/mL against authentic MPXV, was considered to be the putative candidates for MPXV neutralization in response to monkeypox disease.

Isolation and characterization of mpox virus from the first mpox case in Shenzhen, China

•We reported the first MPXV strain hMpxV/China/SZ-SZTH42/2023 isolated in southern China. •The isolate SZTH42 belongs to C.1 lineage of clade IIb, representing the currently prevalent IIb branch strain worldwide. •This study provides key resources and technical platforms for the development of antiviral drugs and vaccines.