Gamma interferon is a defining cytokine of Th1 cells and involved in the downregulation of Th2 cells.

Expression of Foxp3 transcription factor is the best 'marker' that correlates with regulatory T-cell activity.

Antigen drives both T-cell and B-cell responses.

By far, the vast majority of autoimmune diseases involve multiple genes together with environmental factors. IPEX is an example of an extremely small number of autoimmune diseases that are caused by a single gene defect. In this case, mutation of the Foxp3 gene results in a profound defect in regulatory T-cell activity.

In complete DiGeorge syndrome there is a total failure of the thymus to develop and thus neither CD4-positive T-cells nor CD8-positive T-cells are formed. Note, however, that most cases of DiGeorge syndrome are 'partial' with some thymic development and thus not a complete absence of T-cells.

Gamma C deficiency is responsible for about 40% of cases of SCID, and together with JAK 3 deficiency, results in a T-B+NK- phenotype. It is also utilized by the receptors for IL-2, -4, -7, -9 and -21.

Although patients with SLE often develop an immune complex mediated glomerulonephritis, this is not the single best defining feature. Patients with SLE very characteristically possess anti-nuclear antibodies (ANA), including antibodies against DNA.

This is one of the main defining autoantigens in type 1 diabetes along with insulin and IA-2.

The albumin solution is suitable for medical use generally at concentrations of 5-25%. Human albumin is often used to replace lost fluid, and help restore blood volume in trauma, burns and surgery patients.

Germinal centers are produced in secondary lymphoid tissues (lymph nodes, spleen, MALT) when antigen initiates an adaptive immune response.

This is an incorrect statement as the platelets bud off from megakaryocytes, and never have a nucleus.

A glioma is a type of tumor that starts in the brain or spine. It is called a glioma because it arises from glial cells. An increased incidence in gliomas has no association with HIV infection.

When group B blood is transfused to group O recipient, it will cause intravascular haemolysis as the recipient has anti-B antibodies.

CD40 ligand is proclaimed on the surface of the CD4⁺ T cells as a result of the activation that follows the binding of peptide MHC class II to the TCR.

The pneumococcal vaccine encompasses capsular polysaccharides from Streptococcus pneumoniae, and represents a non-viable vaccine, which cannot lead to infection.