Immunoglobulin classes in the garden lizard, Calotes versicolor

Area of Science:

• Immunology
• Comparative immunology
• Reptilian immunology

Background:

• Immunoglobulins (antibodies) are crucial for adaptive immunity.
• Understanding immunoglobulin diversity across species provides insights into immune system evolution.

Purpose of the Study:

• To purify and characterize immunoglobulin classes from lizard serum.
• To determine if lizards possess distinct immunoglobulin isotypes similar to other vertebrates.

Main Methods:

• Ion-exchange chromatography (DEAE-cellulose) for initial purification.
• Gel filtration (Sephadex G-200, Sepharose 6B) for size-based separation.
• SDS-PAGE (Sodium dodecyl sulfate-polyacrylamide gel electrophoresis) to analyze molecular weights of subunits.
• Antisera production and cross-absorption to confirm antibody specificity.

Main Results:

• Two distinct immunoglobulin classes, IgM and IgY, were isolated from lizard serum.
• Lizard IgM is sensitive to 2-mercaptoethanol (2-ME) and shares structural similarities with human IgM.
• Lizard IgY is 2-ME resistant, low molecular weight, and analogous to avian and amphibian IgY.
• SDS-PAGE revealed specific heavy and light chain molecular weights for both lizard IgM and IgY.
• Cross-absorption experiments confirmed IgM and IgY as distinct immunoglobulin isotypes in lizards.

Conclusions:

• Lizards possess at least two distinct immunoglobulin isotypes: IgM and IgY.
• The characterized IgM and IgY molecules exhibit structural features consistent with their counterparts in other vertebrate classes.
• This study contributes to the understanding of immunoglobulin diversity and evolution in reptiles.