The de novo (new) generation of receptors with each cell division in the bone marrow (BCR) or thymus (TCR)

The de novo (new) generation of receptors in response TLR stimulation by microbes

Recombination of the V(D)J gene segments encoded in the genome

Altering the nucleotides that are found between the V(D)J segments of the receptors

1: Eosinophil, 2: Lymphocyte, 3: Neutrophil, 4: Basophil

1: Neutrophil, 2: Lymphocyte, 3: Eosinophil, 4: Basophil

1: Lymphocyte, 2: Basophil, 3: Neutrophil, 4: Eosinophil

1: Basophil, 2: Lymphocyte, 3: Eosinophil, 4: Neutrophil

Both chains of the receptor is generated simultaneously and then dimerise to form the mature receptor

Each chain of the receptor is generated at different times

The cell interacts with external antigens that direct the generation of antigen specific receptors

The cell undergoes negative selection which determines if the cell is able to divide enough to generate lots of cells

Dendritic cells

Thymic cortical epithelial cells

T cells

B cells

1: Basophil, 2: Lymphocyte, 3: Basophil, 4: Neutrophil

1: Neutrophil, 2: Lymphocyte, 3: Eosinophil, 4: Basophil

1: Eosinophil, 2: Lymphocyte, 3: Neutrophil, 4: Macrophage

1: Neutrophil, 2: Macrophage, 3: Lymphocyte, 4: Basophil

The TCR is interacting with MHC that is presenting self-peptides

The TCR interact with MHC that are not presenting any peptide

The TCR does not need to interact with MHC

The TCR is interacting with MHC that is presenting pathogen associated peptides

The MHC molecule expressed by any particular cell is determined by the type of pathogen that is being processed and presented

Siblings will express identical MHC molecules

The number of alleles in the population is increasing rapidly due to selection pressure by novel microbes (such as SARS-COV-2)

All MHC alleles encoded on each chromosome of an individual are expressed

1: Eosinophil, 2: Lymphocyte, 3: Neutrophil, 4: Basophil

1: Neutrophil, 2: Lymphocyte, 3: Eosinophil, 4: Basophil

1: Lymphocyte, 2: Basophil, 3: Neutrophil, 4: Eosinophil

1: Basophil, 2: Lymphocyte, 3: Eosinophil, 4: Neutrophil

Undergo another round of recombination in order generate a new functional receptor

Switch gene expression to the other chromosome in order to generate a new receptor

Leave the thymus and convert to an NK cell that does not require TCR binding to function.

Not interact with its surrounding environment to receive survival signals

 Proteasome

 Tapasin

MHC class I

 Ubiquitin