agglutination

noun

1. (countable, uncountable)The act of uniting by glue or other tenacious substance; the state of being thus united; adhesion of parts.
2. (countable, uncountable)Combination in which root words are united with little or no change of form or loss of meaning. See agglutinative.
3. (countable, uncountable)The clumping together of red blood cells or bacteria, usually in response to a particular antibody.

   “It may resemble the factor 5 in Salmonella, a heat-labile determinant on the endotoxin molecule which, because of its superficial location, blocks the agglutination reaction of the deeper heat-stable O antigens in the same way as do the Vi and K antigens.”