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")
First normal form normal form: our columns contain non-atomic values, and they contain more than one of them. An apparent solution is to introduce more columns: Technically, this table does not violate the requirement for values to be atomic. However, informally, the two telephone number columns still form a "repeating group": they repeat what is conceptually the same attribute, namely a telephone number. An arbitrary and hence meaningless ordering has been introduced: why is 555-861-2025 put into the Telephone Number1 column rather than the Telephone Number2 column? There's no reason why customers could not have more than two telephone numbers, so how many