T-Cell Dependency of T-Independent (TI) Antigens: Antibody Response to Blood Group A-Antigen Requires CD4 T-Cells and CD40/CD40L Interaction
Notice bibliographique
Résumé
Introduction: Polysaccharides are considered TI antigens capable of eliciting antibody secretion without T-cell help. TNP-Ficoll is used as a model TI (type 2) antigen, but detailed mechanisms of B-cell responses remain unclear. We studied a T-cell role in the antibody response to polysaccharides, using a clinically relevant ABO antigen in its natural form. Methods: Mice (4-8 week-old) received three standardized immunizations (days 0- 7- 14) with human blood group-A erythrocyte membranes, TNP-Ficoll or sperm whale myoglobin (SPWM; protein); some groups received first injection in complete Freund's adjuvant then two boosts without adjuvant. For T-cell depletion studies, anti-CD4 (clone GK1.5) or isotype control were injected on day -1-0- +1. To further characterize direct and indirect interaction of CD40/CD40L, CD40L KO mice were injected with anti-CD40 (clone IC10) or isotype control in order to activate or block CD40 on B cells; CD40 KO mice were injected with mouse rCD40-Fc fusion protein to activate T-cells which in turn may activate B-cells through soluble factors. TLR contribution was studied in MyD88 KO. Anti-A antibodies were measured in plasma at day -1-14-21 by hemagglutination and ABO-ELISA, and TNP and SPWM antibodies by ELISA. Results: Natural anti-A antibodies were undetectable on day -1 in all groups, whereas anti-TNP antibody was present in young mice. A-erythrocytes elicited a substantial antibody response, which was abrogated by CD4 T-cell depletion (fig 1), including IgM (fig 2), whereas of SPWM antibodies, only IgG was absent with normal or low IgM and IgA. Antibodies to TNP-Ficoll were comparable in CD4-depleted vs. control mice. Similarly there were no differences in response to secondary A-antigen immunization when CD4 cells were depleted in pre-immunized mice. Anti-A antibodies were significantly reduced in CD40L KO, and further diminished with anti-CD40 antibody; no reduction was seen in MyD88 KO mice. Conclusions: This study clearly demonstrates that antibody response to A-antigen requires CD4 T-cells. Although polysaccharides may not stimulate MHC class II-dependent T-cell help, the presence of activated CD4 T-cells and their interaction with B-cells through CD40-CD40L (fig 2) is critical for B-cells to become antibody secreting cells. These findings have major implications for ABO-incompatible and xenotransplants.[Figure 1][Figure 2]
Récupéré en direct depuis OpenAlex et désinversé. Les résumés ne sont pas conservés dans cette base de données : les index inversés représentent 8,6 Go des 9,3 Go de texte de la base, et le serveur dispose de 13 Go libres.
Comment cette classification a été obtenuedéplier
Prédiction distillée sur la base complète
Imitation des enseignantsNi prévalence calibrée, ni vérité terrain. Validation humaine à venir. Apprise à partir de 10 348 étiquettes directes de Codex et de 10 348 étiquettes directes de Gemma. Le mode candidate est l'union des têtes enseignantes seuillées; le consensus est leur intersection. Ces sorties portent le statut machine_predicted_unvalidated et ne sont ni des étiquettes humaines ni des étiquettes directes de modèles de pointe.
Scores Codex et Gemma par catégorie
| Catégorie | Codex | Gemma |
|---|---|---|
| Métarecherche | 0,001 | 0,000 |
| Méta-épidémiologie (sens strict) | 0,000 | 0,000 |
| Méta-épidémiologie (sens large) | 0,000 | 0,000 |
| Bibliométrie | 0,000 | 0,000 |
| Études des sciences et des technologies | 0,000 | 0,000 |
| Communication savante | 0,000 | 0,000 |
| Science ouverte | 0,000 | 0,000 |
| Intégrité de la recherche | 0,000 | 0,000 |
| Charge utile insuffisante (le modèle a refusé de juger) | 0,000 | 0,000 |
Scores machine (provisoires)
Les deux têtes enseignantes du modèle étudiant, lues sur ce travail. Un score ordonne la base pour la relecture; il n'affirme jamais une catégorie, et le statut de validation accompagne chaque rangée tel quel.
Scores de référence d'un modèle non mature (critères de maturité non atteints, 7 itérations). Un score ordonne; il n'affirme jamais une catégorie.
score_only:v0-immature-baseline · tel quel depuis la passe de notation : score_only signifie que le nombre peut ordonner les travaux, et qu'aucune étiquette de catégorie n'en découleClassification
machine, non validéePrédiction automatique; un appel candidat d’une seule tête enseignante, pas un consensus.
Le détail, modèle par modèle et score par score, se trouve en fin de page sous « Comment cette classification a été obtenue ».