Recovery of central memory and naive peripheral T cells in Follicular Lymphoma patients receiving rituximab-chemotherapy based regimen.

Preclinical models and clinical studies have shown that anti-CD20-based treatment has multifaceted consequences on T-cell immunity. We have performed a prospective study of peripheral T-cell compartment in FL patients, all exhibiting high tumor burden and receiving rituximab-chemotherapy-based regimen (R-CHOP). Before treatment, FL patients harbor low amounts of peripheral naive T cells, but high levels of CD4+ TEM, CD4+ Treg and CD8+ TEMRA subsets and significant amounts of CD38+ HLA-DR+ activated T cells. A portion of these activated/differentiated T cells also expressed PD-1 and/or TIGIT immune checkpoints. Hierarchical clustering of phenotyping data revealed that 5/8 patients with only a partial response to R-CHOP induction therapy or with disease progression segregate into a group exhibiting a highly activated/differentiated T cell profile and a markedly low proportion of naive T cells before treatment. Rituximab-based therapy induced a shift of CD4+ and CD8+ T cells toward a central memory phenotype and of CD8+ T cells to a naive phenotype. In parallel, a decrease in the number of peripheral T cells expressing both PD-1 and TIGIT was detected. These observations suggest that the standard rituximab-based therapy partially reverts the profound alterations observed in T-cell subsets in FL patients, and that blood T-cell phenotyping could provide a better understanding of the mechanisms of rituximab-based treatment.

Keeping the memory of influenza viruses.

Protection against pathogens is mediated by both humoral responses (neutralizing antibodies) and cellular immunity, both CD4+ and CD8+ cells. In the case of influenza viruses, circulating strains contain both variable and conserved T and B cell epitopes that are challenged after vaccination and/or infection. During infection, the role of T cells is to prevent viral dissemination in the organism by killing the infected cells and helping B cell antibody production to neutralize the virus. The threat of influenza virus increases the preparedness of protective immunity to pandemic and seasonal infection by vaccination. Several questions remain that need to be further addressed for the future development of innovative and rapidly efficient vaccines strategies. Firstly, what are the correlates of long-term protection (antibodies and/or T cells) against variant strains of influenza? How does the individual factors (age, natural immunity, vaccination and/or infection history) influence the generation and maintenance of memory cells? What are the factors allowing the maintenance of immune memory (regular contact with the pathogen or re-vaccination)? Secondly, what is the nature and quality (function / phenotype / location) of memory B and T cells? Finally, is it necessary to induce and maintain immunological memory against conserved proteins and/or to re-vaccinate against viral variants? What would be the consequences of repeated vaccination? These questions remain a subject of debate that will be further discussed. Since immunological memory is the cornerstone of vaccination, it is essential that we have a better understanding of its generation and maintenance over time as well as its contribution to recall responses during pandemics or after vaccination.

[Therapeutic monoclonal antibodies: a little history, a lot of engineering, and... some clinical successes]. / Anticorps monoclonaux à usage thérapeutique: un peu d'histoire, beaucoup d'ingénierie, et... quelques succès cliniques.

Thirty years after their discovery by Milstein and Köhler, monoclonal antibodies have now come of age as therapeutics. Nineteen monoclonal antibodies are on the market and/or have got authorization to be used for the treatment of severe diseases. Many technical efforts have been devoted over the last two decades to the generation of second generation mAbs with better affinities, decreased immunogenicity and optimized effector functions. The development of molecular engineering techniques applied to antibody molecules has also made it possible to design bi-specific antibodies and fusion molecules exhibiting different modules with bi-functional activities. The use of proteomics and genomics combined with phage display allows now the rapid selection of antibodies directed against new targets at a high rate. Many efforts are currently focused on the selection of high-responder patients, the optimization of antibody delivery, schemes of infusion, antibody pharmaco-kinetics and bio-distribution, as well as on a better control of the severe side-effects generated by some antibody treatments.