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Trained Immunity in Host Defense: Mechanisms, Pathogen Interactions, and Therapeutic Potential

delete2026-08-11
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OA
AI
F
Farha Siddiqui *
A
Anindita Datta
S
Shivani Choubey
S
Subhasish Bhadra
A
Arif Siddiqui
K
Kalpana Sadawarte
DOI:10.3390/pathogens15080834delete
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Abstract

Abstract

En 中文
Trained immunity refers to the functional reprogramming of innate immune cells—such as monocytes, macrophages, and natural killer cells—those results in a modulated, and often heightened, response to secondary stimuli. This phenomenon challenges the traditional view that immunological memory is restricted to the adaptive immune system and has emerged as a concept linking host defense, vaccination, and inflammatory disease. This review synthesizes current evidence on the molecular basis of trained immunity, including chromatin remodeling, histone modifications, and metabolic rewiring, and examines how bacteria, viruses, and fungi induce, evade, or exploit these programs. The dual contribution of trained immunity to protective host defense and to immunopathology is discussed, along with its implications for vaccine design—including heterologous protection reported after BCG vaccination—and its potential as a therapeutic target in infectious and inflammatory disease. Key gaps, particularly the duration and reversibility of the trained state, the distinction between trained immunity and related processes such as innate tolerance, and the need for validated biomarkers, are highlighted, together with priorities for future translational research.
Keywords:
epigenetic reprogramming
innate immune memory
heterologous immunity

Journal

Pathogens cover
Pathogens
IF:
3.3
Papers:
9.4K
Citations:
2.3W

Organization

A
All India Institute of Medical Sciences
Scholars:
686
Papers: 219
Citations: 6.2K
K
King George's Medical University
Scholars:
644
Papers: 224
Citations: 615
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