Haemocyte heterogeneity in the cockroach Periplaneta americana analysed using monoclonal antibodies

Abstract

A panel of monoclonal antibodies (mAbs) raised against whole haemocytes from Periplaneta americana has revealed two broad categories of immunogens. Three mAbs showed reactivity with membrane-bound antigens on the three major morphological classes of haemocyte as well as the basement membrane of tissues in contact with the haemocoel. Moreover, this reactivity showed heterogeneity within morphotypes: this heterogeneity was quantified using flow cytometry. In contrast, two other mAbs did not show reactivity with tissues other than haemocytes: both mAbs appeared to label unique intracellular components of the haemocytes. We have demonstrated that mAbs can be used to define haemocyte subpopulations in P. americana that are not recognisable on morphological criteria alone. We believe this heterogeneity underlies the mechanisms responsible for the identification and neutralisation of non-self in the ‘immune’ response of P. americana.