The resting memory B cells start secreting detectable level of specific antibodies after receiving ex vivo polyclonal activation8

The resting memory B cells start secreting detectable level of specific antibodies after receiving ex vivo polyclonal activation8. of HBV vaccine. In all of these cases, B-cell ELISpot assay was used effectively in enumerating the frequency of HBs-specific B cells. While the focus of the current report was to establish the utility of this assay for HBV research, a number of interesting observations were made in this pilot study based on the profiles and dynamics of HBs-specific B cells in various conditions. Such information is useful to guide the future work in designing novel therapeutic strategies against CHB. Introduction Hepatitis B computer virus?(HBV) infection remains a major health threat in many parts of the world especially in developing countries including countries with large human populations such as China1. While the introduction of a subunit protein-based HBV vaccine has greatly reduced the rate of new human infections in the last several decades, the population of people who either were infected before the introduction of HBV vaccine or missed the chance of getting vaccinated is still quite large2. Existing therapies can only partially control the infection but MT-7716 hydrochloride not remedy the diseases3,4. Obtaining novel treatment strategies especially an immune therapy is usually critically needed. The significance of vaccine-induced antibody (HBsAb) responses against HBV surface antigen (HBsAg) in protecting against HBV infection has been well established5,6. However, HBsAb is basically missing in chronic HBV-infected patients. How to break bodys immune tolerance MT-7716 hydrochloride to elicit protective HBsAb that can control the viral contamination is a major challenge in HBV research. The level of serum HBsAb has been used as the gold standard in determining the success of HBV vaccination7. Scientists have also assigned the induction of serum HBsAb as the biomarker for clinical remedy of HBV contamination. However, since most experimental immune therapies have not achieved this goal, there is a great need to develop option biomarkers to detect any early indicators of immune activation against HBV contamination. In theory, HBsAb is produced by hepatitis B surface?antigen (HBs)-specific B cells and the presence of HBs-specific memory B cells may be an indication of potential HBsAb responses. Unfortunately, such assessments have not been well established or widely used to monitor the level of circulating HBs-specific memory B cells in human peripheral blood. In the current study, we investigated the levels of HBs-specific B cells in the peripheral blood of 21 HBV vaccine immunized healthy individuals and 67 patients with different immunological phases of chronic HBV contamination. The relationship between the titer of serum HBsAb and the level of HBs-specific B cells was analyzed. Furthermore, the dynamic switch of HBs-specific memory B KSR2 antibody cells after either vaccination or antiviral treatment was monitored in this pilot study. Information learned from the current study would be useful to better understand the basic immunological mechanisms that are involved in the induction and maintenance of HBsAb as part of the effort to develop novel immune therapies against chronic HBV contamination. Results HBs-specific memory B cells in healthy adults with history of HBV vaccination A sensitive B-cell ELISpot assay was used in the current study to detect and MT-7716 hydrochloride enumerate HBs-specific memory B cells from human peripheral blood mononuclear cells (PBMCs) among healthy adult vaccinees. Human PBMCs were cultured for 5 days in the presence of R848 and IL-2. The resting memory B cells start secreting detectable level of specific antibodies after receiving ex vivo polyclonal activation8. Among people who had been vaccinated with HBV vaccine in the past, HBs-specific memory B cells would be detected by the HBs-specific B cell ELISpot assay. HBsAb secreted by these B cells were captured by recombinant HBsAg antigen coated around the ELISpot plates, further demonstrated by colored spots revealed around the plates following the addition of biotinylated anti-human IgG antibody and HRP-conjugated streptavidin. As shown in Fig.?1a, representative B cell ELISpot assay results revealed HBsAb-secreting B cells from two individuals (HC9 and HC21) in the healthy.