Highest molecular weight immunoglobulins are

Ref: Ananthanarayan and Paniker's, 8th ed. pg. 100Immunoglobulins and their salient featuresImmuno-globulinsSalient featuresIgG* Most abundant Ig, makes as about 80%* Marker of chronic infection* Only Ig that can cross placentaIgA* 2nd most abundant, 10-13%* Found in glandular secretion like saliva, tear, ileum, and mucosal secretion like bronchial secretionIgM* 5-8% of total Ig; aka pentameric Ig - has highest molecular weight* First Ig to be synthesized by fetus (20 weeks AOG)* Marker of acute infectionIgD* Present mostly intravascular* Serve as recognition receptor for antigensIgE* Mostly extravascular in distribution* Highly elevated levels in case of type-I HPS reaction* Produced chiefly in the linings of respiratory and intestinal tractsImmunoglobulin and their effective valencyAntibodyEffective valency* IgM5* IgG2* IgD2* IgE2* IgA2,4* Ig having maximum molecular weight: IgM* First antibody produced by newborn: IgM* All immunoglobulins are heat stable except: IgE* Ig present in breast milk: IgA* Ig with maximum half-life: IgG* Ig with minimum half-life: IgE* Ig having maximum serum concentration: IgG* Ig having least serum concentration: IgE