Helminth Immune Response Flashcards

This set of vocabulary flashcards covers the stages of the adaptive immune response, T-cell differentiation (Th1, Th2, Th17, Treg), the specific mechanisms of the type 2 immune response against helminths involving ILC2s, Tuft cells, and eosinophils, and the associated pathologies.

Phase 1 of Adaptive Immune Response

Antigen recognition, involving the capture and presentation of antigens by dendritic cells.

Langerhans cell

An immature dendritic cell located in the epidermis that captures antigens and migrates to the lymph nodes to become a mature dendritic cell.

Signal 1 in T cell activation

The interaction between the Peptide-MHC complex on a dendritic cell and the TCR on a T cell.

Signal 2 in T cell activation

The co-stimulatory interaction between $CD80/86$ on the dendritic cell and $CD28$ on the T cell.

Signal 3 in T cell activation

The secretion of cytokines, such as $IL-12$ for Th1 differentiation, that influences T cell polarization.

Th1 subset

A T helper subset characterized by the master transcription factor $Tbet$, producing $IFN-\text{γ}$ and $IL-2$ for cell-mediated immunity against intracellular pathogens.

Th2 subset

A T helper subset characterized by the master transcription factor $Gata-3$, producing $IL-4$, $IL-5$, and $IL-13$ for humoral immunity against helminths.

Th17 subset

A T helper subset characterized by the master transcription factor $ROR\text{γ}t$, producing $IL-17A$ and $IL-22$ in response to extracellular bacteria and fungi.

Treg subset

Regulatory T cells characterized by the master transcription factor $FoxP3$, producing $IL-10$ and $TGF-\text{β}$ for immune suppression and mucosal homeostasis.

Alternative macrophage activation

Activation of macrophages by $IL-4$ and $IL-13$ secreted by Th2 cells, primarily involved in tissue repair.

Major Basic Protein (MBP)

A toxic protein released by activated eosinophils to mediate the killing of helminths.

Eosinophil Cationic Protein (ECP)

A protein release by eosinophils via $FcR$-mediated activation to help destroy helminthic parasites.

Tuft cell

A specialized epithelial cell in the small intestine that identifies helminths (via succinate and $SUCNR1$) and produces $IL-25$ to activate ILC2s.

ILC2 (Group 2 Innate Lymphoid Cells)

Innate lymphoid cells that respond to $IL-25$, $IL-33$, and $TSLP$ to produce $IL-5$ and $IL-13$ for helminth defense and allergic inflammation.

Goblet cell hyperplasia

An increase in mucus-producing goblet cells in the intestinal epithelium, induced by $IL-13$ during a helminth infection.

Basophils in helminth response

Cells that produce $IL-4$ and respond to $IL-33$ and $TSLP$ to support the differentiation of Th2 cells and B cell IgE production.

M cells

Specialized cells in the Gut-Associated Lymphoid Tissue (GALT) that deliver bacteria and antigens from the intestinal lumen to dendritic cells and Peyer's patches.

Granulomatous Reaction

A chronic inflammatory response, such as that seen in $Schistosoma \text{ } mansoni$ infection, which can lead to severe fibrosis and cirrhosis.

Epileptogenesis in Helminth Infection

The development of epilepsy as a pathology of neurocysticercosis, caused by inflammation, calcification, and perilesional edema.

Carcinogenesis associated with Helminths

The development of cancers such as cholangiocarcinoma (bile duct cancer), bladder cancer, or hepatocarcinoma due to helminthic infection.