Robust and Persistent B- and T-Cell Responses after COVID-19 in Immunocompetent and Solid Organ Transplant Recipient Patients

Abstract

The development and persistence of SARS-CoV-2-specific immune response in immunocompetent (IC) and immunocompromised patients is crucial for long-term protection. Immune response to SARS-CoV-2 infection was analysed in 57 IC and 15 solid organ transplanted (TX) patients. Antibody responses were determined by ELISA and neutralization assay. T-cell response was determined by stimulation with peptide pools of the Spike, Envelope, Membrane, and Nucleocapsid proteins with a 20-h Activation Induced Marker (AIM) and 7-day lymphoproliferative assays. Antibody response was detected at similar levels in IC and TX patients. Anti-Spike IgG, IgA and neutralizing antibodies persisted for at least one year, while anti-Nucleocapsid IgG declined earlier. Patients with pneumonia developed higher antibody levels than patients with mild symptoms. Similarly, both rapid and proliferative T-cell responses were detected within the first two months after infection at comparable levels in IC and TX patients, and were higher in patients with pneumonia. T-cell response persisted for at least one year in both IC and TX patients. Spike, Membrane, and Nucleocapsid proteins elicited the major CD4+ and CD8+ T-cell responses, whereas the T-cell response to Envelope protein was negligible. After SARS-CoV-2 infection, antibody and T-cell responses develop rapidly and persist over time in both immunocompetent and transplanted patients.

Durability of anti-spike antibodies after vaccination with mRNA SARS-CoV-2 vaccine is longer in subjects with previous infection: could the booster dose be delayed?

“…At 240 days after the vaccine there was a significant difference in mean level of RBD S-protein IgG in previously SARS-CoV-2 infected subjects than in the uninfected individuals. This robust and persistent immunological response was probably the consequence of the memory B-cell and T-cell response to natural viral infection [ 7 ]. In this moment, it is unclear what the extent of antibody titers means for the risk of a future infection.…”

mRNA BNT162b Vaccine Elicited Higher Antibody and CD4+ T-Cell Responses than Patients with Mild COVID-19

“…The S-specific proliferative response was determined as previously described [3]. Briefly, PBMCs (600,000/200 µL culture medium per well) were stimulated in triplicate with S and human actin peptide pools (15 mers, overlapping by 10 amino acids, Pepscan, Lelystad, The Netherlands) at a final concentration of 0.1 µg/mL for 7 days.…”

“…Immunization against SARS-CoV-2, the causative agent of a global outbreak of a respiratory tract disease referred to as COVID-19, occurs via natural infection or vaccination. Several studies reported that higher titres of IgG and neutralising antibodies (Nt Ab) were detected in patients with severe SARS-CoV-2 infection compared to patients with mild symptoms [1][2][3][4][5][6][7]. SARS-CoV-2 spike (S) protein reactive T-cells were identified in immunocompetent (IC) patients suffering from moderate, severe, and critical COVID-19 [8], and a dominance of CD4 + T-cell over CD8 + T-cell response was observed in severe and mild COVID-19 patients [9].…”

“…SARS-CoV-2 spike (S) protein reactive T-cells were identified in immunocompetent (IC) patients suffering from moderate, severe, and critical COVID-19 [8], and a dominance of CD4 + T-cell over CD8 + T-cell response was observed in severe and mild COVID-19 patients [9]. In addition, patients with pneumonia developed higher memory CD4 + and CD8 + T-cell responses than patients with mild symptoms [3]. Immunological memory could persist for at least 15 months after infection [3,[10][11][12][13], and may protect the IC population from SARS-CoV-2 secondary infections [14].…”

“…In addition, patients with pneumonia developed higher memory CD4 + and CD8 + T-cell responses than patients with mild symptoms [3]. Immunological memory could persist for at least 15 months after infection [3,[10][11][12][13], and may protect the IC population from SARS-CoV-2 secondary infections [14]. The mRNA vaccine BNT162b2 [15] was approved after showing safety and a 95% efficacy in preventing COVID-19 [16].…”