Cross-reactivity IgG, viral load, severity and vaccination outcome as an approach for understanding humoral immune response against SARS-CoV-2


Por: Contreras-Villa, J, Rodríguez-Martínez, G, Parra-Ortega, I, Romo-Castillo, M, Cortés-Sarabia, K, Saldaña-Ahuactzi, Z, Flores-Alanis, A, Aureoles-Romero, A, Salazar-García, M, González, J, Eslava-Campos, CA, Hernández-Chiñas, U, Cruz-Rangel, A, Morales-Espinosa, R, Cancino-Diaz, ME, Luna-Pineda, VM

Publicada: 18 nov 2025
Resumen:
BackgroundSerological evaluation plays a crucial role in understanding cross-reactivity, the prevalence of infection, immune response in COVID-19 disease, asymptomatic infections, and vaccine effectiveness.MethodsRecombinant spike (rS) and Nucleocapsid (rN) proteins from SARS-CoV-2 were used to determine IgG antibodies (Abs) in serum samples obtained from Mexican adults and paediatrics before and during the pandemic by enzyme-linked immunosorbent assay.ResultsHuman sera from 2003 to 2016 showed higher levels of cross seropositivity (54.5-75%) against rS and rN. In serum samples from adult patients with COVID-19, the reactivity intensity (RI) depended on the severity of the disease, whereas in convalescent paediatric patients with COVID-19, SARS-CoV-2 viral load depended on sex and comorbidities. Regarding vaccine effectiveness monitoring, an increased RI of anti-rS IgG was observed in people vaccinated against COVID-19 who had a natural infection with SARS-CoV-2. During the vaccination scheme, an increase in IgG Abs level was observed with the second dose, whereas a decrease was observed after six months of vaccination. Vaccine boosters increased RI in either homologous/heterologous administration of mRNA and non-replicating viral vector vaccines.ConclusionsEpidemiological outbreaks and the circulation of non-SARS-CoV-2 coronaviruses may contribute to the primary causes of the observed cross-reactions in antibodies. Furthermore, factors such as viral load and disease severity in infected patients, prior illnesses, the dosage of vaccine and booster shots, and the type of vaccine used in COVID-19-vaccinated individuals may also influence the increase in IgG antibodies. Assessing the antibody-based humoral immune response in serum samples collected before and during an outbreak or pandemic could aid in comprehending emerging and re-emerging diseases and developing effective preventive strategies.Clinical trial numberNot applicable.

Filiaciones:
Contreras-Villa, J:
 Hosp Infantil Mexico Dr Federico Gomez, Lab Invest Patogenos Resp, Mexico City, Mexico

 Inst Politecn Nacl, Escuela Nacl Ciencias Biol, Dept Inmunol, Mexico City, Mexico

Rodríguez-Martínez, G:
 Hosp Infantil Mexico Dr Federico Gomez, Lab Invest Patogenos Resp, Mexico City, Mexico

Parra-Ortega, I:
 Hosp Infantil Mexico Dr Federico Gomez, Dept Lab Clin, Mexico City, Mexico

Romo-Castillo, M:
 Hosp Infantil Mexico Dr Federico Gomez, Lab Invest Patogenos Resp, Mexico City, Mexico

 Hosp Infantil Mexico Dr Federico Gomez, Consejo Nacl Ciencia Human & Tecnol, IxM, Mexico City, Mexico

Cortés-Sarabia, K:
 Univ Autonoma Guerrero, Fac Ciencias Quim Biol, Lab Inmunobiol & Diagnost Mol, Chilpancingo De Los Bravo, Guerrero, Mexico

Saldaña-Ahuactzi, Z:
 Inst Politecn Nacl, Ctr Invest Biotecnol Aplicada, Tepetitla De Lardizabal, Tlaxcala, Mexico

Flores-Alanis, A:
 Univ Nacl Autonoma Mexico, Fac Med, Dept Microbiol & Parasitol, Mexico City, Mexico

Aureoles-Romero, A:
 Hosp Infantil Mexico Dr Federico Gomez, Lab Invest Patogenos Resp, Mexico City, Mexico

Salazar-García, M:
 Hosp Infantil Mexico Dr Federico Gomez, Lab Biol Desarrollo Teratogenesis Expt, Mexico City, Mexico

González, J:
 Univ Nacl Autonoma Mexico, Fac Ciencias, Dept Biol Celular, Mol Biol Lab, Mexico City 04510, DF, Mexico

Eslava-Campos, CA:
 Univ Nacl Autonoma Mexico, Hosp Infantil Mexico Federico Gomez, Fac Med, Lab Patogen Bacteriana, Mexico City, Mexico

Hernández-Chiñas, U:
 Univ Nacl Autonoma Mexico, Hosp Infantil Mexico Federico Gomez, Fac Med, Lab Patogen Bacteriana, Mexico City, Mexico

Cruz-Rangel, A:
 Inst Nacl Med Genomica, Lab Bioquim Enfermedades Cron, Mexico City, Mexico

Morales-Espinosa, R:
 Univ Nacl Autonoma Mexico, Fac Med, Dept Microbiol & Parasitol, Mexico City, Mexico

Cancino-Diaz, ME:
 Inst Politecn Nacl, Escuela Nacl Ciencias Biol, Dept Inmunol, Mexico City, Mexico

Luna-Pineda, VM:
 Hosp Infantil Mexico Dr Federico Gomez, Lab Invest Patogenos Resp, Mexico City, Mexico
ISSN: 14712334
Editorial
BIOMED CENTRAL LTD, 236 GRAYS INN RD, FLOOR 6, LONDON WC1X 8HL, ENGLAND, Reino Unido
Tipo de documento: Article
Volumen: 25 Número: 1
Páginas:
WOS Id: 001618437900003
ID de PubMed: 41254630
imagen Green Submitted, gold

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