Amaranthus leucocarpus lectin (ALL) Enhances anti-CD3-Dependent Activation of Murine T Cells and Promotes Cell Survival

Abstract

The Galβ1,3GalNAc-specific lectin from Amaranthus leucocarpus (ALL) shows a differential binding pattern on murine thymocytes, peripheral and activated CD4⁺ and CD8⁺ T cells. Although ALL detects activation-related changes in T cell surface carbohydrate moieties, no study has been performed to examine the effect of ALL on T cell activation. In this study, we analyzed the anti-CD3-dependent activation of murine T cells in the presence of ALL by measuring proliferation, surface activation marker expression, and IL-2 secretion using total cells from the lymph node. The results showed that ALL did not significantly induce T cell activation but did enhance anti-CD3-dependent activation of both CD4⁺ and CD8⁺ T cells. In addition, ALL protected T cells from spontaneous apoptosis and increased cell survival in serum-free culture conditions. Our findings indicate that ALL alone does not affect T cell activation, but do suggest that ALL has an anti-CD3-dependent co-stimulatory-like effect on T cell activation. Moreover, ALL promotes cell survival in regular and serum-free culture conditions. This study is the first report of a non-mitogenic T cell-binding lectin that can induce a possible costimulatory-like effect and provides a new tool for understanding how glycosylation impacts the T cell response.

Keywords:

• Amaranthus leucocarpus
• Lectins
• Glycosylation
• T-cell activation

ACKNOWLEDGMENTS

The authors thank Dr. Alberto Pizaña Venegas for his help during the experimental animal management. We also thank Dr. Moises Selman and Felipe Mendoza for providing access to the FACSAria flow cytometer. This work was supported in part by PAPIIT-UNAM (IN214609).

Declaration of interest: The authors report no conflict of interest. The authors alone are responsible for the content and writing of the paper.