Cell surface molecules

Only the toxins produced by viruses

The virus

The virus and cell surface molecules

The ability to present to, and activate, T cells is equal

Activated dendritic cells will only present antigen in MHC class II

Immature DCs are predominantly found in the draining lymph nodes

Immature DCs have a lower expression of MHC molecules on their surface

TCR

CD4 (if the interaction is with MHC class II) or CD8 (if the interaction is with MHC class I) co-receptors

Integrin

MHC

Form a bridge between the TCR and CD3 allowing the immunological synapse to form

Translocate to the nucleus to switch on T cell activation genes

Modify the molecular structure of the CD3 and ζ (zeta) chains

Bring the CD4 co-receptor closer to the TCR so it can bind to the non-polymorphic α2 and β2 domains of the MHC class II molecule

Lck binds to CD4 and leads to phosphorylation of ITAM

Lck binds to CD3 to induce direct signalling through the TCR

Lck binds to the ITAMs and leads to phosphorylation

Lck binds to the TCR cytoplasmic tail and CD4 to link and increase the avidity between the APC and T cell

The antibody binding to complement that has already coated the pathogen

Antibodies that have precoated macrophages, bind to, and capture pathogens for phagocytosis

The antibody binding to the pathogen via the CDR loops

The antibody binding to the pathogen via its Fc region

Enhance antigen presentation by dendritic cells

Stimulate TH17 cells to co-operate with CTLs to eliminate intracellular pathogens

Engage with IL-17 receptors on neutrophils, driving their migration to site of infection

Promote expression of IL-1 by epithelial cells

Increased body temperature

IgE antibody production

Smooth muscle contraction

Mucus secretion

Increase the binding strength at the antigen binding site

The swapping of one light chain for another that will improve antigen recognition

Direct the B cell to make a specific class of antibody, for example IgE 

Increase the number of immunoglobulin molecules that are bound together to make the antibody

B cells are found equally distributed throughout the lymph node

B cells will be located close to the efferent lymphatic vessel draining antigen from the lymph node

B cells will surround dendritic cells presenting antigens to naive T cells to generate follicles

B cells will be localised in regions governed by expression of chemokine receptors