tetano
Editor, Senior Moderator
Cell Rep
. 2026 Mar 6;45(3):117052.
doi: 10.1016/j.celrep.2026.117052. Online ahead of print.
Repeated COVID-19 vaccine boosters elicit variant-specific memory B cells in humans
M Alejandra Tortorici[SUP] 1 [/SUP], Kaitlin R Sprouse[SUP] 2 [/SUP], Amin Addetia[SUP] 1 [/SUP], Jack T Brown[SUP] 1 [/SUP], Jimin Lee[SUP] 1 [/SUP], Cameron Stewart[SUP] 1 [/SUP], Benjamin Merz[SUP] 1 [/SUP], Alex Harteloo[SUP] 3 [/SUP], Anna Elias-Warren[SUP] 3 [/SUP], Helen Y Chu[SUP] 4 [/SUP], David Veesler[SUP] 5 [/SUP]
Affiliations
The first exposure to a pathogen impacts subsequent immune responses toward related pathogens. This immune imprinting explains that infection or vaccination with circulating SARS-CoV-2 variants primarily recalls cross-reactive memory B cells induced by prior Wuhan-Hu-1 (Wu) spike (S) exposure. The magnitude and persistence of immune imprinting in mRNA vaccinees are not understood. We investigate serum antibody and memory B cell responses after administration of multiple XBB.1.5 and JN.1/KP.2 COVID-19 vaccine boosters. We find that the JN.1/KP.2 booster elicits broadly neutralizing antibody responses against recent SARS-CoV-2 variants by recalling Wu S-induced immunity in all but one individual. We detect an increased fraction of serum antibodies, and particularly memory B cells, recognizing XBB.1.5 and KP.2, but not Wu, relative to individuals who received a single XBB.1.5 booster. Repeated exposures to antigenically divergent S thus contribute to overcoming immune imprinting and support vaccine updates for continued protection.
Keywords: COVID-19 vaccines; CP: immunology; SARS-CoV-2 spike glycoprotein; antigenic sin; coronaviruses; immune imprinting; immunology; memory B cells; neutralizing antibodies; serum antibodies; virology.
. 2026 Mar 6;45(3):117052.
doi: 10.1016/j.celrep.2026.117052. Online ahead of print.
Repeated COVID-19 vaccine boosters elicit variant-specific memory B cells in humans
M Alejandra Tortorici[SUP] 1 [/SUP], Kaitlin R Sprouse[SUP] 2 [/SUP], Amin Addetia[SUP] 1 [/SUP], Jack T Brown[SUP] 1 [/SUP], Jimin Lee[SUP] 1 [/SUP], Cameron Stewart[SUP] 1 [/SUP], Benjamin Merz[SUP] 1 [/SUP], Alex Harteloo[SUP] 3 [/SUP], Anna Elias-Warren[SUP] 3 [/SUP], Helen Y Chu[SUP] 4 [/SUP], David Veesler[SUP] 5 [/SUP]
Affiliations
- PMID: 41800618
- DOI: 10.1016/j.celrep.2026.117052
The first exposure to a pathogen impacts subsequent immune responses toward related pathogens. This immune imprinting explains that infection or vaccination with circulating SARS-CoV-2 variants primarily recalls cross-reactive memory B cells induced by prior Wuhan-Hu-1 (Wu) spike (S) exposure. The magnitude and persistence of immune imprinting in mRNA vaccinees are not understood. We investigate serum antibody and memory B cell responses after administration of multiple XBB.1.5 and JN.1/KP.2 COVID-19 vaccine boosters. We find that the JN.1/KP.2 booster elicits broadly neutralizing antibody responses against recent SARS-CoV-2 variants by recalling Wu S-induced immunity in all but one individual. We detect an increased fraction of serum antibodies, and particularly memory B cells, recognizing XBB.1.5 and KP.2, but not Wu, relative to individuals who received a single XBB.1.5 booster. Repeated exposures to antigenically divergent S thus contribute to overcoming immune imprinting and support vaccine updates for continued protection.
Keywords: COVID-19 vaccines; CP: immunology; SARS-CoV-2 spike glycoprotein; antigenic sin; coronaviruses; immune imprinting; immunology; memory B cells; neutralizing antibodies; serum antibodies; virology.