Mucosal Immunology and Biology Research Center, Massachusetts General Hospital for Children, 114 16(th) Street, Charlestown, MA 02129, USA.
Mucosal Immunology and Biology Research Center, Massachusetts General Hospital for Children, 114 16(th) Street, Charlestown, MA 02129, USA; Pediatric Allergy and Immunology and Center for Immunology and Inflammatory Disease, Massachusetts General Hospital, 175 Cambridge Street, Boston, MA 02114, USA.
Cell Rep Med. 2023 Dec 19;4(12):101298. doi: 10.1016/j.xcrm.2023.101298. Epub 2023 Nov 27.
SARS-CoV-2 mRNA vaccines elicit humoral responses in children that are comparable to those in adults. However, early-life T cell responses are distinct from adult ones, and questions remain about the nature and kinetics of mRNA vaccine-induced T cell responses in children. We report that Pfizer BNT162b2 mRNA vaccination elicits a significant antigen-specific CD4 T cell response in the ≥12-year-old cohort. This response is weaker in magnitude in the 5- to 11-year-old cohort and is not improved by a higher vaccine dose (Moderna mRNA1273, 100 μg), suggesting distinct developmental programming that may underscore early-life T cell immunity. Increased effector phenotypes of antigen-specific T cells in younger children correspond with elevated anti-receptor binding domain antibody levels, albeit at the cost of memory generation. These studies highlight aspects of age-specific adaptive immune responses and the need for careful consideration of priming conditions including vaccine dose and adjuvant in the pediatric population.
SARS-CoV-2 mRNA 疫苗可在儿童体内引发体液免疫应答，其应答强度与成人相当。然而，儿童的 T 细胞应答与成人存在差异，mRNA 疫苗诱导的 T 细胞应答的性质和动力学仍存在诸多问题。我们报告称，辉瑞 BNT162b2 mRNA 疫苗可在≥12 岁的儿童群体中引发显著的抗原特异性 CD4 T 细胞应答。在 5 至 11 岁的儿童群体中，该应答的强度较低，且增加疫苗剂量（Moderna mRNA1273，100μg）并不能改善这种情况，这表明存在不同的发育编程，可能凸显了儿童早期的 T 细胞免疫。在年龄较小的儿童中，抗原特异性 T 细胞的效应表型增加，同时抗受体结合域抗体水平升高，尽管是以牺牲记忆细胞生成为代价的。这些研究强调了年龄特异性适应性免疫应答的各个方面，以及在儿科人群中需要仔细考虑包括疫苗剂量和佐剂在内的初始条件。
