Table 1.
Teleosts | Mammals | |
---|---|---|
Primary organs | Thymus/head kidney | Thymus/bone marrow |
Secondary organs | Spleen | Spleen/lymph nodes |
Mucosa-associated lymphoid tissues |
+ (no Peyer’s Patch) |
+ |
Germinal centers/FDCs | −a | + |
B cells | ||
Immunoglobulins | ||
Heavy chain (locus configuration) | IgD, IgM, IgT/Zb (translocon)c |
IgD, IgM, IgA, IgG, IgE (translocon) |
Light chain (locus configuration) | Kappa, lambda, sigma, sigma cart (multi-cluster) |
Kappa/lambda (translocon/multi cluster) |
Somatic hypermutation | + | + |
Affinity maturation | Low efficiency | High efficiency |
Class switch | − | + |
T cells | ||
CD4/CD8 subsets | +d | + |
Th1/Th2/Th17 | + | + |
TCR αβ/γδ | + | + |
FDCs follicular dendritic cell
Putative primordial germinal centers have been characterized
In medaka and catfish the IgT/Z has not been identified
More than one functional IgH locus in most of studied teleost species
Absence of the cd4 and mhc II functional genes in some species (e.g. cod and pipefish)