Immunoglobulin A only weakly. IgA exists in two isotypes, IgA1 and IgA2. They are both heavily glycosylated proteins. While IgA1 predominates in serum (~80%), IgA2 percentages are higher in secretions than in serum (~35% in secretions); the ratio of IgA1 and IgA2 secreting cells varies in the different lymphoid tissues of the human body: Both IgA1 and IgA2 have been found in external secretions like colostrum, maternal milk, tears and saliva, where IgA2 is more prominent than in the blood. Polysaccharide antigens tend to induce more IgA2 than protein antigens. Both IgA1 and IgA2 can be in membrane-bound form. ("see B-cell receptor")
Prenex normal form "all" be written in universal-existential form, a special case of the prenex normal form that has every universal quantifier preceding any existential quantifier, so that all sentences can be rewritten in the form formula_79 formula_80 formula_81 formula_82 formula_83 formula_46, where formula_46 is a sentence that does not contain any quantifier. This fact allowed Tarski to prove that Euclidean geometry is decidable. Prenex normal form A formula of the predicate calculus is in prenex normal form if it is written as a string of quantifiers and bound variables, called the prefix, followed by a quantifier-free part, called the matrix. Every formula