Animal Immunology

Animal immunology encompasses the multifaceted defence systems that enable organisms to resist infection, maintain homeostasis and respond to environmental challenges. Evolutionary pressures have shaped two complementary arms of immunity: an ancient innate system that provides immediate, non-specific protection via pattern-recognition receptors, phagocytic cells and antimicrobial peptides; and an adaptive system acquiring specificity and memory through lymphocyte antigen receptors and immunoglobulins. These systems coordinate via cytokine networks and co-stimulatory signals to detect pathogens, orchestrate inflammation and regulate tissue repair. Across vertebrates and invertebrates, conserved molecular modules—such as Toll-like receptors, NOD-like receptors and the complement cascade—mediate the initial response, while specialised antigen-presenting cells bridge to B- and T-lymphocyte activation in vertebrates. Practical applications of animal immunology span vaccine design for livestock and aquaculture, immunotherapy in veterinary and human medicine, and the use of animal models to dissect host–pathogen interactions. Emerging research integrates genomics, cellular immunology and metabolic pathways to unravel how nutrition, microbiota and environmental stressors influence immune competence, with global implications for food security, zoonotic disease control and wildlife conservation.

Research from Nature Portfolio

Recent analyses of individuals recovering from severe respiratory virus infection have revealed persistent dysregulation of iron homeostasis linked to chronic inflammation and aberrant erythropoiesis. Single-cell profiling identified monocyte iron loading and increased iron demand in proliferating lymphocytes, correlating with long-term symptom persistence. This work underscores the role of nutrient regulation in post-infectious immune sequelae.

Complementary mechanistic studies have shown that iron-dependent histone demethylases are essential for activated B-cell proliferation and antibody production. Inhibition of these enzymes or dietary iron deficiency impaired cyclin E1 expression, S-phase entry and vaccine-induced humoral responses, highlighting an epigenetic axis through which iron availability controls adaptive immunity.

Research from all publishers

In vitro coculture experiments demonstrated that direct interactions with macrophages increase the susceptibility of triple-negative cancer cells to ferroptosis by elevating intracellular ferrous iron and lipid peroxidation. This suggests that immune-cell crosstalk can be harnessed to enhance iron-dependent cell death in tumours.

Studies in Atlantic salmon have shown that exposure to CpG oligodeoxynucleotides drives mononuclear phagocytes to acquire dendritic-like morphology, a proinflammatory transcriptional profile and altered co-stimulatory receptor expression, despite attenuating allostimulatory capacity. These findings reveal conserved pathways of antigen-presenting cell differentiation in teleosts.

Quantitative genetic analyses of Pacific oysters across larval, juvenile and adult stages estimated moderate heritability for resistance to Ostreid herpesvirus 1 and Vibrio aestuarianus infections, with no significant genetic correlation between the two traits. This indicates potential for selective-breeding programmes to improve disease resilience in aquaculture species.

Animal Immunology publication trend

The graph below shows the total number of articles in animal immunology across all publications each year (not limited to Nature Index journals).

Technical terms

Pattern-recognition receptor (PRR): Germline-encoded receptor that binds conserved microbial molecules to initiate innate immune signalling.

Co-stimulatory molecule: Cell-surface protein (e.g., CD28, CD80/86) whose interaction is required for full lymphocyte activation.

Ferroptosis: Regulated form of cell death caused by iron-dependent lipid peroxidation.

Histone demethylase: Enzyme that removes methyl groups from histones, affecting gene transcription in an iron-dependent manner.

Gene conversion: Mechanism in some species that diversifies immunoglobulin genes by templated sequence replacement from pseudogenes.

Adaptive immunity: Immune responses characterised by antigen-specific lymphocyte receptors and immunological memory.

References

1. Iron dysregulation and inflammatory stress erythropoiesis associates with long-term outcome of COVID-19. Nature Immunology (2024).
2. Iron-dependent histone 3 lysine 9 demethylation controls B cell proliferation and humoral immune responses. Nature Communications (2019).
3. Coculture with macrophages alters ferroptosis susceptibility of triple-negative cancer cells. Cell Death Discovery (2024).
4. CpGs Induce Differentiation of Atlantic Salmon Mononuclear Phagocytes Into Cells With Dendritic Morphology and a Proinflammatory Transcriptional Profile but an Exhausted Allostimulatory Activity. Frontiers in Immunology (2019).
5. Genetic parameters of resistance to Vibrio aestuarianus, and OsHV-1 infections in the Pacific oyster, Crassostrea gigas, at three different life stages. Genetics Selection Evolution (2017).