Ectopic lymphoid follicles: inducible centres for generating antigen‐specific immune responses within tissues

Abstract

SummaryLymphoid neogenesis is traditionally viewed as a pre‐programmed process that promotes the formation of lymphoid organs during development. Here, the spatial organization of T and B cells in lymph nodes and spleen into discrete structures regulates antigen‐specific responses and adaptive immunity following immune challenge. However, lymphoid neogenesis is also triggered by chronic or persistent inflammation. Here, ectopic (or tertiary) lymphoid organs frequently develop in inflamed tissues as a response to infection, auto‐immunity, transplantation, cancer or environmental irritants. Although these structures affect local immune responses, the contribution of these lymphoid aggregates to the underlining pathology are highly context dependent and can elicit either protective or deleterious outcomes. Here we review the cellular and molecular mechanisms responsible for ectopic lymphoid neogenesis and consider the relevance of these structures in human disease.

Intratumoral injection of a CpG oligonucleotide reverts resistance to PD-1 blockade by expanding multifunctional CD8 + T cells

“…S1B), diminished the response to anti-PD-1, suggesting that CXCL13 is a key chemokine contributing to anti-PD-1 effect. CXCL13 is a master chemokine able to organize ectopic lymphoid structures (25,29,30), and its neutralization may affect PD-1 blockade by destroying the organization of T-cell priming structures. A decrease in B-cell infiltration may also lead to a decrease in B-cell-mediated antigen presentation and costimulation for T cells (31)(32)(33)(34)(35).…”

Aspectos patológicos e imuno-histoquímicos da polisserosite em búfalos (Bubalus bubalis)

“…Os folículos linfoides ectópicos são estruturas transitórias formadas particularmente em reações inflamatórias onde há persistência do patógeno ou antígeno (Neyt et al 2012, Jones & Jones 2016. Esta organização do infiltrado na forma de folículos ectópicos foi considerada uma importante evidência da base inflamatória da lesão.…”

“…Estas marcações imuno--histoquímicas demonstraram um predomínio de linfócitos T no infiltrado em relação aos linfócitos B. Linfócitos T auxiliares são constituintes importantes dos folículos linfoides terciários (Jones & Jones, 2016), sendo importantes na sua formação juntamente com as células dendríticas (Neyt et al 2012, Jones & Jones 2016. Os linfócitos CD79 positivos predominaram no centro das estruturas foliculares.…”

“…Os linfócitos CD79 positivos predominaram no centro das estruturas foliculares. Este é padrão de distribuição esperado para os linfócitos B em tecidos linfoides secundários e terciários (Neyt et al 2012, Jones & Jones 2016. Assim o padrão de distribuição dos linfócitos T e B no infiltrado determinado através da imuno-histoquímica também corrobora a base inflamató-ria da lesão.…”

CXCL13-producing TFH cells link immune suppression and adaptive memory in human breast cancer

“…It is required for early recruitment of lymphoid tissue inducer cells and functions upstream of other early signals, including the lymphotoxin-β receptor (8). De novo TLS formation in chronically inflamed tissues has been correlated with allograft rejection, autoimmune disease progression (9), and improved cancer outcomes (10).…”