Variations in Monocytic Response to Peroxydase Test.

Abstract

Naegeli states that almost all, if not all, of the human monocytes are peroxydase reacting. The author found no peroxydase-reacting monocytes in the blood of a rabbit. In a normal adult man there were present 3.4% peroxydase mononuclear phagocytes and 1.1% phagocytes that did not react to the peroxydase test. The conclusion was that the peroxydase cells of human blood are of myeloid origin, which is the view held by Naegeli. The negative phagocytes were thought to be the true monocytes derived from the reticular portion of lymphoid tissue. Recently some unpublished observations have brought me to a consideration of the alternative view, namely, that the peroxydase-positive phagocyte gets its granulation secondarily in a more or less accidental manner. The conclusions arrived at in this paper are based on tissue cultures of blood leukocytes. Methods and Results: Numerous cultures of human blood were made by the coverglass method and examined by the peroxydase test daily from one day to 4 weeks. This was done on the assumption that the peroxydase granulation of the monocytes would disappear, provided the granulation was acquired secondarily and was not an essential part of the cell cytoplasm. After one month in the incubator large peroxydase reacting phagocytes were present in the cultures. Never was the number of phagocytes great and no conclusion was possible in regard to the proportion of positive and negative cells. Rhoads and Parker found at the end of 2 weeks of incubation both positive and negative mononuclear phagocytes in normal human blood. The next procedure was to culture rabbit leukocytes in contact with variable amounts of human blood: Rabbit blood was cultured on sterile cover-glasses covered with smears of human blood made with aseptic precautions. The smears were kept dry in the air for 2 hours. The rabbit blood was obtained from the heart and drops of blood placed directly on the covers from the small caliber needle. The covers which had previously been rimmed with sterile vaseline were inverted over the well and placed in the incubator within 5 minutes after withdrawal of the blood from the heart. After about one hour the covers were sealed permanently with paraffin. At the end of 2 weeks as many as 500 large mononucleated cells were present in some of the cultures while in the human blood cultures mentioned above the cells at the most numbered a few dozen.