Project description:COVID-19 mRNA vaccines generate high concentrations of circulating anti-Spike antibodies and Spike-specific CD4+ T cells following prime-boost vaccination. It is not yet clear if vaccine-induced CD4+ T cell responses in the draining lymph node contribute to this outstanding immunogenicity. Using fine needle aspiration of draining axillary lymph nodes from individuals who received the BNT162b2 mRNA vaccine, we found large populations of Spike-specific CD4+ T follicular helper cells in the draining lymph node. A broadly immunodominant HLA-DPB1*04-restricted response to Spike166-180 composes one of the largest populations of T follicular helper cells in individuals with this allele, which is itself among the most common HLA alleles in the human population. Spike-specific T follicular helper cells are present in the lymph node 30 days after vaccine boost and persist in some individuals more than 170 days. Collectively, our results underscore the key role that robust T follicular helper cell responses play in the establishment of long-term immunity in this very efficacious human vaccine.
Project description:Heterologous ChAdOx1-BNT162b2 vaccination induces a stronger immune response than two doses of BNT162b2. Yet, the molecular transcriptome, the germline allelic variants of immunoglobulin loci and anti-Omicron antibody levels induced by the heterologous vaccination have not been formally investigated. Moreover, there is a paucity of COVID-19 vaccine studies including diverse genetic populations. Here, we show a robust molecular immune transcriptome and antibody repertoire in 46 office and lab workers from the Republic of Korea after heterologous vaccination, ChAdOx1 followed by BNT162b2. Anti-spike-specific IgG antibody levels against the ancestral SARS-CoV-2 strain increased from 70 AU/ml immediately following the first vaccination to 14,000 U/ml within three days after the second vaccination and 142,000 AU/ml after seven days. Antibody titers against more recent variants, including Omicron, were two- to three-fold lower, yet higher than those obtained after the second dose of a BNT162b2-BNT162b2 homologous vaccination. RNA-seq conducted on peripheral immune cells demonstrated a strong activation of interferon-induced genetic programs in the heterologous cohort and an increase of specific IGHV clonal transcripts encoding neutralizing antibodies was detected. Enrichment of B cell and CD4+ T cell responses was observed following both ChAdOx1-BNT162b2 heterologous and BNT162b2-BNT162b2 homologous vaccination using scRNA-seq, but clonally expanded memory B cells were relatively stronger in the heterologous cohort. In summary, a heterologous vaccination with ChAdOx1 followed by BNT162b2 provides an innate and adaptive immune response exceeding that seen in homologous BNT162b2 vaccination.
Project description:Heterologous ChAdOx1-BNT162b2 vaccination induces a stronger immune response than BNT162b2-BNT162b2. Here we investigated the molecular transcriptome, germline allelic variants of immunoglobulin loci, and anti-Omicron antibody levels in 46 office and lab workers from the Republic of Korea following ChAdOx1-BNT162b2 vaccination. Anti-spike-specific IgG antibody levels against the ancestral SARS-CoV-2 strain increased from 70 AU/ml to 14,000 AU/ml to 142,000 AU/ml one, three and seven days following the second vaccination. Titers against VOC, including Omicron, were two- to three-fold lower, yet higher than those measured following BNT162b2-BNT162b2 vaccination. RNA-seq of peripheral immune cells demonstrated activation of interferon pathways with increased IGHV clonal transcripts encoding neutralizing antibodies. scRNA-seq revealed enriched B cell and CD4+ T cell responses in both ChAdOx1-BNT162b2 and BNT162b2-BNT162b2 recipients, but a stronger clonal expansion of memory B cells with ChAdOx1-BNT162b2. In summary, heterologous ChAdOx1-BNT162b2 provides an innate and adaptive immune response that exceeds homologous BNT162b2 vaccination.
Project description:Heterologous ChAdOx1-BNT162b2 vaccination induces a stronger immune response than two doses of BNT162b2. Yet, the molecular transcriptome, the germline allelic variants of immunoglobulin loci and anti-Omicron antibody levels induced by the heterologous vaccination have not been formally investigated. Moreover, there is a paucity of COVID-19 vaccine studies including diverse genetic populations. Here, we show a robust molecular immune transcriptome and antibody repertoire in 46 office and lab workers from the Republic of Korea after heterologous vaccination, ChAdOx1 followed by BNT162b2. Anti-spike-specific IgG antibody levels against the ancestral SARS-CoV-2 strain increased from 70 AU/ml immediately following the first vaccination to 14,000 U/ml within three days after the second vaccination and 142,000 AU/ml after seven days. Antibody titers against more recent variants, including Omicron, were two- to three-fold lower, yet higher than those obtained after the second dose of a BNT162b2-BNT162b2 homologous vaccination. RNA-seq conducted on peripheral immune cells demonstrated a strong activation of interferon-induced genetic programs in the heterologous cohort and an increase of specific IGHV clonal transcripts encoding neutralizing antibodies was detected. Enrichment of B cell and CD4+ T cell responses was observed following both ChAdOx1-BNT162b2 heterologous and BNT162b2-BNT162b2 homologous vaccination using scRNA-seq, but clonally expanded memory B cells were relatively stronger in the heterologous cohort. In summary, a heterologous vaccination with ChAdOx1 followed by BNT162b2 provides an innate and adaptive immune response exceeding that seen in homologous BNT162b2 vaccination.
Project description:SARS-CoV-2 mRNA vaccines induce robust anti-spike (S) antibody and CD4+ T cell responses. It is not yet clear whether vaccine-induced follicular helper CD4+ T (TFH) cell responses contribute to this outstanding immunogenicity. Using fine-needle aspiration of draining axillary lymph nodes from individuals who received the BNT162b2 mRNA vaccine, we evaluated the T cell receptor sequences and phenotype of lymph node TFH. Mining of the responding TFH T cell receptor repertoire revealed a strikingly immunodominant HLA-DPB1∗04-restricted response to S167-180 in individuals with this allele, which is among the most common HLA alleles in humans. Paired blood and lymph node specimens show that while circulating S-specific TFH cells peak one week after the second immunization, S-specific TFH persist at nearly constant frequencies for at least six months. Collectively, our results underscore the key role that robust TFH cell responses play in establishing long-term immunity by this efficacious human vaccine.
Project description:Analysis of in vivo antigen-specific (LCMV-specific, SMARTA TCR transgenic) follicular helper CD4 T cells (CXCR5high),versus non-follicular helper CD4 T cells (CXCR5low), eight days after viral infection. A paper including data analysis of these experiments has been accepted for publication (Robert J. Johnston et al. Bcl6 and Blimp-1 are reciprocal and antagonistic regulators of follicular helper CD4 T cell differentiation). Experiment Overall Design: Analysis of in vivo antigen-specific (LCMV-specific, SMARTA TCR transgenic) follicular helper CD4 T cells (CXCR5high), versus non-follicular helper CD4 T cells (CXCR5low), eight days after viral infection.
Project description:T follicular helper (Tfh) cells provide signals to initiate and maintain the germinal center (GC) reaction and are crucial for the generation of robust antibody responses. We found that hypoxia inducible factor-1 (HIF-1a) is an inhiibitor of Tfh generation in a mouse model of acute viral infection, and that HIF-1a mediates its effects by suppressing mTORC1 activity.