. Author manuscript; available in PMC: 2013 Jun 1.

Published in final edited form as: Infect Disord Drug Targets. 2012 Jun;12(3):200–212. doi: 10.2174/187152612800564419

Table 1.

Summary of Features from B Cells and Immunoglobulins of Vertebrates

Vertebrate Spleen Class Thymus	VLR-Producing Lymphocytes	Ig-Producing Lymphocytes	Ig Classes	Affinity Maturation		Class Switch	L. Nodes/G. Centers

Agnathan fish	+	-	-	?	-	-	No spleen, but thymuslike structure

Cartilaginous fish	-	+	IgM, IgW	Poor	-	-	+
Cartilaginous fish	-	+	IgNAR	Poor	-	-	+

Teleost fish	-	+	gM, IgD	Poor	-	-	+
Teleost fish	-	+	IgT	Poor	-	-	+

Amphibians	-	+	IgM, IgY	Poor	+	+	+
Amphibians	-	+	IgX, IgD	Poor	+	+	+

Reptiles	-	+	IgM, IgY	?	+	+	+
Reptiles	-	+	IgA (?)	?	+	+	+

Birds	-	+	IgM, IgY	Medium	+	+	+
Birds	-	+	IgA	Medium	+	+	+

Mammals	-	+	IgM, IgG	High	+	+	+
			IgA, IgD
			IgE

Abbreviations: Ig=Immunoglobulin; L. nodes= Lymph nodes; G. centers= Germinal Centers.