Immunogenicity and safety of a recombinant fusion protein vaccine (V-01) against coronavirus disease 2019 in healthy adults: a randomized, double-blind, placebo-controlled, phase II trial / 中华医学杂志(英文版)

BACKGROUND@#Innovative coronavirus disease 2019 (COVID-19) vaccines, with elevated global manufacturing capacity, enhanced safety and efficacy, simplified dosing regimens, and distribution that is less cold chain-dependent, are still global imperatives for tackling the ongoing pandemic. A previous phase I trial indicated that the recombinant COVID-19 vaccine (V-01), which contains a fusion protein (IFN-PADRE-RBD-Fc dimer) as its antigen, is safe and well tolerated, capable of inducing rapid and robust immune responses, and warranted further testing in additional clinical trials. Herein, we aimed to assess the immunogenicity and safety of V-01, providing rationales of appropriate dose regimen for further efficacy study.@*METHODS@#A randomized, double-blind, placebo-controlled phase II clinical trial was initiated at the Gaozhou Municipal Centre for Disease Control and Prevention (Guangdong, China) in March 2021. Both younger (n = 440; 18-59 years of age) and older (n = 440; ≥60 years of age) adult participants in this trial were sequentially recruited into two distinct groups: two-dose regimen group in which participants were randomized either to follow a 10 or 25 μg of V-01 or placebo given intramuscularly 21 days apart (allocation ratio, 3:3:1, n = 120, 120, 40 for each regimen, respectively), or one-dose regimen groups in which participants were randomized either to receive a single injection of 50 μg of V-01 or placebo (allocation ratio, 3:1, n = 120, 40, respectively). The primary immunogenicity endpoints were the geometric mean titers of neutralizing antibodies against live severe acute respiratory syndrome coronavirus 2, and specific binding antibodies to the receptor binding domain (RBD). The primary safety endpoint evaluation was the frequencies and percentages of overall adverse events (AEs) within 30 days after full immunization.@*RESULTS@#V-01 provoked substantial immune responses in the two-dose group, achieving encouragingly high titers of neutralizing antibody and anti-RBD immunoglobulin, which peaked at day 35 (161.9 [95% confidence interval [CI]: 133.3-196.7] and 149.3 [95%CI: 123.9-179.9] in 10 and 25 μg V-01 group of younger adults, respectively; 111.6 [95%CI: 89.6-139.1] and 111.1 [95%CI: 89.2-138.4] in 10 and 25 μg V-01 group of older adults, respectively), and remained high at day 49 after a day-21 second dose; these levels significantly exceed those in convalescent serum from symptomatic COVID-19 patients (53.6, 95%CI: 31.3-91.7). Our preliminary data show that V-01 is safe and well tolerated, with reactogenicity predominantly being absent or mild in severity and only one vaccine-related grade 3 or worse AE being observed within 30 days. The older adult participants demonstrated a more favorable safety profile compared with those in the younger adult group: with AEs percentages of 19.2%, 25.8%, 17.5% in older adults vs. 34.2%, 23.3%, 26.7% in younger adults at the 10, 25 μg V-01 two-dose group, and 50 μg V-01 one-dose group, respectively.@*CONCLUSIONS@#The vaccine candidate V-01 appears to be safe and immunogenic. The preliminary findings support the advancement of the two-dose, 10 μg V-01 regimen to a phase III trial for a large-scale population-based evaluation of safety and efficacy.@*TRIAL REGISTRATION@#http://www.chictr.org.cn/index.aspx (No. ChiCTR2100045107, http://www.chictr.org.cn/showproj.aspx?proj=124702).

Cellular immune responses of recombinant hepatitis B(rHB)vaccine and HBsAg derived from Hansenular polymorpha cells / 中华流行病学杂志

Objective To study the kinetics of immune response in mice and human immunized with rHB vaccine or rHBsAg derived from yeast cells(Hansenula polymorpha).Methods With different doses,the level of IFN-γ secreted by spleen mononuclear cells(MNC)including CD8+T cells by MACs of mice were detected by enzyme-linked immunospot(ELISPOT)methods after stimulation in vitro with HBsAg MHC class Ⅰ peptide S28-39,respectively.At serial time points.the immunized mice were detected for IFN-γ by ELISPOT as above and for the lymphocytotoxicity test(CTL)by specific lysis assay.The levels of IFN-γ,IL-2,IL-5 and anti-HBs in mice induced by rHB vaccine were detected after single or three doses.Four adults were vaccinated with rHB vaccine according to 0,1 and 2 month schedule.The peripheral blood mononuclear cells(PBMCs)were collected at the 3,8,21,34 and 65 days after the first dose.The CD8+T cells with high purity obtained by sorting from PBMcs were stimulated with rHBsAg or HBsAg peptides.The SFC of IFN-γ,IL-2 and IL-4 of CD4+ and CD8+ T cells were determined by ELISPOT.Results The cytokine of IFN-γ became detectable on day 7 and its peak value appeared on day 14 by ELISPOT.The CTL was detected on day 7 and the maximum lysis of CTL appeared on day 28.The cellular immune response of IFN-γ of MNCs were significantly correlated with the doses vaccinated from 1 μg to 8 μg(Υpositive rates=0.951,Ppositive rates=0.049＜0.05;rSFC=0.996,PSFC=0.000＜0.05).IFN-γSFC of CD8+T cells were significantly associated with the doses from 1 μg to 4 μg(Υ=0.999,P=0.025＜0.05).The HBsAg specific cellular immune and humoral responses of mice immunized with three doses were significantly higher than that with a single dose(P＜0.05).The characteristics of IFN-γ,IL-2 and IL-4 of CD4+ and CD8+ T cells were variable between individuals immunized with the same rHB vaccine.The level of IL-2 and IL-4 of responders were significantly related to the titer of anti-HBs.Conclusion Data from this study showed the kinesis of cellular immunity in mice and adults vaccinated with rHBsAg or rHB vaccine respectively.and the characteristics of cellular immune response in adults induced by the vaccine.Our data provided the basis of standardizing the analysis of cellular immune response to rHB vaccine.

Comparison of the kinesis of immune responses in mice vaccinated by different kinds of recombinant hepatitis B vaccines / 中华流行病学杂志

<p><b>OBJECTIVE</b>To evaluate the kinesis of cellular and humoral immune responses to different kinds of recombinant hepatitis B(rHB) vaccines in the immunized mice.</p><p><b>METHODS</b>At serial time points, the levels of IFN-gamma and IL-2 secreted by spleens mononuclear cells (MNC) of the vaccinated mice were detected by enzyme-linked immunospot methods (ELISPOT) after stimulation in vitro with HBsAg MHC class I peptide S28-39 or HBsAg. The lymphocytotoxicity of the immunized mice were also detected (CTL) by a specific lysis assay and the levels of anti-HBs were measured by the Abbott IMX kit.</p><p><b>RESULTS</b>The peak values of IFN-gamma and IL-2 in vaccinated mice were detected by ELISPOT, 10 - 14 days after immunization. The CTL and the level of IFN-gamma induced by rHB vaccine derived from yeast cells (Hansenula polymorpha) (rHP vaccine) were significantly higher than the other two vaccines (P < 0.05). The maximum lysis of CTL appeared in the vaccinated mice on day 10 after immunization, with the percentage of 39.8%. The levels of IL-2 induced by rHP vaccine were significantly higher than the other two vaccines (P < 0.05). However, the IL-2 levels in the rSC (saccharomyces cerevisiae) vaccine group were higher as compared with the rCHO vaccine group at day 7 and day 14 (7 d t = 4.595, P = 0.001 < 0.05; 14 d t = 5.721, P = 0.000 < 0.05) after immunization. The cellular immune response to the rHP vaccine was the strongest while it was the lowest to the rCHO vaccine at day 7 after immunization. The sero-positive rates and the titers of anti-HBs in the vaccinated mice increased with time after vaccination. The titers of anti-HBs in the rCHO vaccine group at day 7 were similar to the rSC vaccine group, but significantly higher than that of the rHP vaccine group (P = 0.044 < 0.05). The anti-HBs titers of the rCHO vaccine group at day 14 were significantly higher as compared to the rSC (P = 0.012 < 0.05) and rHP (P = 0.009 < 0.05) vaccine groups.</p><p><b>CONCLUSION</b>The immune responses induced by the three kinds of rHB vaccines were different in their patterns and levels. According to the intensity of early cellular immune response, the two yeast HB vaccines were superior to the rCHO vaccine, especially to the rHP vaccine. In contrast, the rCHO vaccine induced early seroconversion and high levels of anti-HBs.</p>

Studies on the status of immune memory after completion of hepatitis B vaccination / 中华流行病学杂志

<p><b>OBJECTIVE</b>To study the immune memory in vaccinees after the completion of a full schedule hepatitis B immunization.</p><p><b>METHODS</b>One thousand and two hundred one infants born in 1987 -1989 were immunized with 3 doses of plasma derived hepatitis B vaccine, while 2484 newborn babies during 1996-1999 were injected with 3 doses of the yeast recombinant hepatitis B vaccine. All of the infants under observation were tested for HBsAg, anti-HBs and anti-HBc, in 2005. Of 959 individuals negative for anti-HBs (< 10 mIU/ml), HBsAg and anti-HBc, 228 were immunized with plasma-derived vaccine and 731 with yeast recombinant vaccine after birth. All of them were detected for anti-HBs 15 days after a booster of 10 Ipg yeast recombinant vaccine. In addition, interleukin-2 (IL-2) was detected in 11 non-responders and 22 responders after boostering, using an enzyme-linked immunospot (ELISPOT). The anti-HBs levels of 190 individuals (91 with plasma derived vaccine and 99 with yeast recombinant vaccine) who had had quantitative data on their antibody status after the primary hepatitis B vaccination, were compared with that after the boostering.</p><p><b>RESULTS</b>Among the individuals who received plasma derived vaccine 16-18 years ago, 79.82% of them showed the signs of immune memory after one booster, with a geometric mean titer (GMT)of 325.69 mIU/ml. Of the individuals who received the yeast recombinant vaccine 6-9 years ago, 95.62% showed immune memory after one booster,with its GMT of 745.18 mIU/ml. Anti-HBs levels induced by the booster were associated with that after the primary immunization. The positive rate of IL-2 was 40.91% in subjects with good immune memory. However, IL-2 was not detected in non-responders after the booster (P < 0.01).</p><p><b>CONCLUSION</b>Most of the individuals who had received a completed schedule of primary hepatitis B vaccination and seroconverted from anti-HBs positive to negative,showed the signs of having immune memory after the booster. Only a small proportion of the vaccinees had lost their immune memory during the long term follow-up period, suggesting that these individuals should receive a booster of hepatitis B vaccine in the highly endemic areas of hepatitis B. Hepatitis B virus; Immune memory; Booster immunization</p>

Study on the kinesis of cellular immunity in adults vaccinated with recombinant hepatitis B vaccine / 中华流行病学杂志

<p><b>OBJECTIVE</b>To evaluate the kinesis of cellular immunity in adults who were vaccinated with yeast recombinant hepatitis B(rHB) vaccine and the correlation between cellular and humoral immune responses induced by the vaccine.</p><p><b>METHODS</b>Eight adults were vaccinated with rHB vaccine according to 0, 1,2 month schedule. The peripheral blood mononuclear cells(PBMCs) were collected at the 3, 8, 21, 34 and 65 days after the first dose. The high purity of CD4+ and CD8+ T cells obtained by sorting from PBMCs were restimulated with recombinant hepatitis B surface antigens (rHBsAg) or peptides. The spot forming cell (SFC) of IFN-gamma, IL-2 and IL-4 of CD4+ and CD8+ T cells were detected by enzyme-linked immunospot (ELISPOT).</p><p><b>RESULTS</b>The characteristics of IFN-gamma, IL-2 and IL-4 of CD4+ and CD8+ T cells appeared different after immunization with rHB vaccine. IFN-gamma of CD8+ and CD4+ T cells could be detected early with stable SFC, while the IL-2 and IL-4 of CD4+ T cells appeared late but increased after the second and third dose of vaccination. The positive rate of IL-4 of CD4+ T cells were significantly correlated with the positive rate of anti-HBs, while the SFCs of IL-4 and IL-2 of CD4+ T cells were also significantly related to the titers of anti-FIBs.</p><p><b>CONCLUSION</b>IFN-gamma could be detected early after rHB vaccination in adults, and the positive rates of IL-4 and IL-2 were correlated with that of anti-HBs.</p>