Serological responses to smallpox A33 antigen and monkeypox A35 antigen in healthy people and people living with HIV-1 from Guangzhou, China.

People are expected to have been previously vaccinated with a Vaccinia-based vaccine, as until 1980 smallpox vaccination was a standard protocol in China. It is unclear whether people with smallpox vaccine still have antibody against vaccinia virus (VACV) and cross-antibody against monkeypox virus (MPXV). Herein, we assessed the binding antibodies with antigen of VACV-A33 and MPXV-A35 in the general population and HIV-1 infected patients. Firstly, we detected VACV antibody with A33 protein to evaluate the efficiency of smallpox vaccination. The result show that 29% (23 of 79) of hospital staff (age ≥ 42 years) and 63% (60 of 95) of HIV-positive patients (age ≥ 42 years) from Guangzhou Eighth People's Hospital were able to bind A33. However, among the subjects below 42 years of age, 1.5% (3/198) of the hospital volunteer samples and 1% (1/104) of the samples from HIV patients were positive for antibodies against A33 antigen. Then, we assessed the specific cross-reactive antibodies against MPXV A35 protein. 24% (19 of 79) hospital staff (age〉 = 42 years) and 44% (42 of 95) of HIV-positive patients (age〉 = 42 years) were positive. 98% (194/198) of the hospital staff and 99% (103/104) of the HIV patients had no A35-binding antibodies. Further, we found significant sex differences for the reactivity to A35 antigen were observed in HIV population, but no significant sex differences in hospital staff. Further, we analyzed the positivity rate of anti-A35 antibody of men who have sex with men (MSM) and non-MSM in HIV patients (age〉 = 42years). We found that 47% of no-MSM population and 40% of MSM population were positive for A35 antigen, with no significant difference. Lastly, we found only 59 samples were positive for anti-A33 IgG and anti-A35 IgG in all participants. Together, we demonstrated A33 and A35 antigens binding antibodies were detected in HIV patients and general population who were older than 42 years, and cohort studies only provided data of serological detection to support early response to monkeypox outbreak.

Imaging of Virus-Infected Cells with Soft X-ray Tomography.

Viruses are obligate parasites that depend on a host cell for replication and survival. Consequently, to fully understand the viral processes involved in infection and replication, it is fundamental to study them in the cellular context. Often, viral infections induce significant changes in the subcellular organization of the host cell due to the formation of viral factories, alteration of cell cytoskeleton and/or budding of newly formed particles. Accurate 3D mapping of organelle reorganization in infected cells can thus provide valuable information for both basic virus research and antiviral drug development. Among the available techniques for 3D cell imaging, cryo-soft X-ray tomography stands out for its large depth of view (allowing for 10 µm thick biological samples to be imaged without further thinning), its resolution (about 50 nm for tomographies, sufficient to detect viral particles), the minimal requirements for sample manipulation (can be used on frozen, unfixed and unstained whole cells) and the potential to be combined with other techniques (i.e., correlative fluorescence microscopy). In this review we describe the fundamentals of cryo-soft X-ray tomography, its sample requirements, its advantages and its limitations. To highlight the potential of this technique, examples of virus research performed at BL09-MISTRAL beamline in ALBA synchrotron are also presented.