BNT162b2 vaccine induces neutralizing antibodies and poly-specific T cells in humans.

BNT162b2, a nucleoside-modified mRNA formulated in lipid nanoparticles that encodes the SARS-CoV-2 spike glycoprotein (S) stabilized in its prefusion conformation, has demonstrated 95% efficacy in preventing COVID-191. Here we extend a previous phase-I/II trial report2 by presenting data on the immune response induced by BNT162b2 prime-boost vaccination from an additional phase-I/II trial in healthy adults (18-55 years old). BNT162b2 elicited strong antibody responses: at one week after the boost, SARS-CoV-2 serum geometric mean 50% neutralizing titres were up to 3.3-fold above those observed in samples from individuals who had recovered from COVID-19. Sera elicited by BNT162b2 neutralized 22 pseudoviruses bearing the S of different SARS-CoV-2 variants. Most participants had a strong response of IFNγ+ or IL-2+ CD8+ and CD4+ T helper type 1 cells, which was detectable throughout the full observation period of nine weeks following the boost. Using peptide-MHC multimer technology, we identified several BNT162b2-induced epitopes that were presented by frequent MHC alleles and conserved in mutant strains. One week after the boost, epitope-specific CD8+ T cells of the early-differentiated effector-memory phenotype comprised 0.02-2.92% of total circulating CD8+ T cells and were detectable (0.01-0.28%) eight weeks later. In summary, BNT162b2 elicits an adaptive humoral and poly-specific cellular immune response against epitopes that are conserved in a broad range of variants, at well-tolerated doses.

Plastin 3 is upregulated in iPSC-derived motoneurons from asymptomatic SMN1-deleted individuals.

Spinal muscular atrophy (SMA) is a devastating motoneuron (MN) disorder caused by homozygous loss of SMN1. Rarely, SMN1-deleted individuals are fully asymptomatic despite carrying identical SMN2 copies as their SMA III-affected siblings suggesting protection by genetic modifiers other than SMN2. High plastin 3 (PLS3) expression has previously been found in lymphoblastoid cells but not in fibroblasts of asymptomatic compared to symptomatic siblings. To find out whether PLS3 is also upregulated in MNs of asymptomatic individuals and thus a convincing SMA protective modifier, we generated induced pluripotent stem cells (iPSCs) from fibroblasts of three asymptomatic and three SMA III-affected siblings from two families and compared these to iPSCs from a SMA I patient and control individuals. MNs were differentiated from iPSC-derived small molecule neural precursor cells (smNPCs). All four genotype classes showed similar capacity to differentiate into MNs at day 8. However, SMA I-derived MN survival was significantly decreased while SMA III- and asymptomatic-derived MN survival was moderately reduced compared to controls at day 27. SMN expression levels and concomitant gem numbers broadly matched SMN2 copy number distribution; SMA I presented the lowest levels, whereas SMA III and asymptomatic showed similar levels. In contrast, PLS3 was significantly upregulated in mixed MN cultures from asymptomatic individuals pinpointing a tissue-specific regulation. Evidence for strong PLS3 accumulation in shaft and rim of growth cones in MN cultures from asymptomatic individuals implies an important role in neuromuscular synapse formation and maintenance. These findings provide strong evidence that PLS3 is a genuine SMA protective modifier.

VPA response in SMA is suppressed by the fatty acid translocase CD36.

Functional loss of SMN1 causes proximal spinal muscular atrophy (SMA), the most common genetic condition accounting for infant lethality. Hence, the hypomorphic copy gene SMN2 is the only resource of functional SMN protein in SMA patients and influences SMA severity in a dose-dependent manner. Consequently, current therapeutic approaches focus on SMN2. Histone deacetylase inhibitors (HDACi), such as the short chain fatty acid VPA (valproic acid), ameliorate the SMA phenotype by activating the SMN2 expression. By analyzing blood SMN2 expression in 16 VPA-treated SMA patients, about one-third of individuals were identified as positive responders presenting increased SMN2 transcript levels. In 66% of enrolled patients, a concordant response was detected in the respective fibroblasts. Most importantly, by taking the detour of reprograming SMA patients' fibroblasts, we showed that the VPA response was maintained even in GABAergic neurons derived from induced pluripotent stem cells (iPS) cells. Differential expression microarray analysis revealed a complete lack of response to VPA in non-responders, which was associated with an increased expression of the fatty acid translocase CD36. The pivotal role of CD36 as the cause of non-responsiveness was proven in various in vitro approaches. Most importantly, knockdown of CD36 in SMA fibroblasts converted non- into pos-responders. In summary, the concordant response from blood to the central nervous system (CNS) to VPA may allow selection of pos-responders prior to therapy. Increased CD36 expression accounts for VPA non-responsiveness. These findings may be essential not only for SMA but also for other diseases such as epilepsy or migraine frequently treated with VPA.

Evaluation of SNPs in miR-146a, miR196a2 and miR-499 as low-penetrance alleles in German and Italian familial breast cancer cases.

Recently, the SNPs rs11614913 in hsa-mir-196a2 and rs3746444 in hsa-mir-499 were reported to be associated with increased breast cancer risk, and the SNP rs2910164 in hsa-mir-146a was shown to have an effect on age of breast cancer diagnosis. In order to further investigate the effect of these SNPs, we genotyped a total of 1894 breast cancer cases negative for disease-causing mutations or unclassified variants in BRCA1 and BRCA2, and 2760 controls from Germany and Italy. We compared the genotype and allele frequencies of rs2910164, rs11614913 and rs3746444 in cases versus controls of the German and Italian series, and of the two series combined; we also investigated the effect of the three SNPs on age at breast cancer diagnosis. None of the performed analyses showed statistically significant results. In conclusion, our data suggested lack of association between SNPs rs2910164, rs11614913 and rs3746444 and breast cancer risk, or age at breast cancer onset.