Immunologlobin A or IgA



Immunologlobin A or IgA

History

In the year 1890 Kitasato and von Behring showed that the blood of rabbit is inoculated with the toxin of tetanus which had the activity against the poison. This blood serum was when transferred to the rabbits then it saved these animals against the tetanus. In the year 1901 he was given the Nobel Prize for that. Ehrlich also confirmed that this protection is related to the amount of antitoxins that are present in the blood.

Chemical structure

The main structural unit of all the antibodies of the mammals is a glycoprotein and it consists of four polypeptide chains among which two chains are heavy and the two chains are light and they are connected together by the disulfide bonds. Every light chain has the molecular weight of ~25,000 daltons and it is made up of two domains. One is the constant domain (CL) and variable domain (VL). There are two types of light chains in the immunoglobin, one is kappa (?) and the other is lambda (?). In the human beings almost 40% of the chains are lambda and 60% are kappa. In mice, 5% chains are lambda and the 95% of the chains are kappa. An antibody molecule contains lambda chains or kappa chains but they do not contain both chains.

The molecular weight of the heavy chains is ~50,000 daltons and it has a variable and constant region. The light chains and the variable chains have several homologous sections which have same group of amino acid sequences. There are about 110 amino acids which are called as the immunoglobulin domains. The heavy chains have about three or four constant domains and one variable domain. The regions that are among the CH1 and CH2 are the hinge regions and they allow the flexibility in the two Fab arms of the antibody molecule which is Y shaped. There can be either one or more than one units in the IgA antibodies (Woof & Russell, 2011).

Procedure

The IgA MAbs can be produced by with the help of two methods. The first method depends on the use of the transgenic mouse. The human a1 gene is introduced in the location of the switch sequence Sµ7 which helps in the separation of the main chimeric IgA MAbs with the help of the basic hybridoma method. In the second method recombinant DNA technologies and hybridoma technique ...