Lois B. Epstein

The interaction of human macrophages and lymphocytes in the phytohemagglutinin-stimulated production of interferon

In studies of 13 normal adults to determine the blood cell types responsible for interferon production induced by phytohemagglutinin, the following observations were made. (a) In cultures containing 96-100% pure macrophages derived from blood monocytes, no interferon was detected in either the presence or the absence of phytohemagglutinin for up to 92 hr. (b) In cultures of 99.5-100% pure lymphocytes, low levels of interferon were detected in the presence, but not in the absence, of phytohemagglutinin. (c) An average fivefold increase in interferon titers occurred when pure lymphocytes were combined with the macrophages in culture with phytohemagglutinin. The peak response of interferon occurred at 68 hr after the initiation of the combined cultures. For maximum response, phytohemagglutinin was required for the duration of the culture, and both cell types in association were necessary. Medium from phytohemagglutinin-stimulated macrophages or lymphocytes could not substitute for the corresponding intact cell. However, frozen-thawed macrophages in combination with lymphocytes and phytohemagglutinin produced an intermediate interferon response. An increase in either cell type produced an increased response in the range studied: lymphocytes, 0.45-1.8 x 10(6) per ml; and macrophages, 0.5-2.1 x 10(5) per ml. Syngeneic fibroblasts, HeLa cells, or mouse macrophages could not substitute for the human macrophages in the combined cultures with phytohemagglutinin. (d) Although all cultures producing interferon showed some degree of transformation (thymidine-(3)H incorporation into deoxyribonucleic acid), no direct correlation between the degree of phytohemagglutinin-induced lymphocyte transformation and the interferon titers was observed.The demonstration of macrophage-lymphocyte interaction in the production of interferon is of interest in view of the known interrelationship of these same cell types in antibody synthesis and cellular immunity.

Fluorescence-activated cell sorting of human T and B lymphocytes: II. Identification of the cell type responsible for interferon production and cell proliferation in response to mitogens☆

Abstract We have employed the fluorescence-activated cell sorter to separate pure viable preparations of human T and enriched B lymphocytes. Using such preparations, we have demonstrated that both human T and B cells can respond to PHA and PWM in vitro in the presence of macrophages with proliferation and the production of interferon, a mediator of cellular immunity. However, selective T cell interferon production and proliferative response can be assessed at 3 days in culture; B cell interferon production and proliferative response is delayed to 5 and 7 days. T cells or T cell products are ineffective in inducing or accelerating B cell interferon or proliferative response at 3 days. The use of 3-day T cell interferon production as a new technique for the assessment of T cell effector function and competence is suggested.

PPD-stimulated interferon: In vitro macrophage-lymphocyte interaction in the production of a mediator of cellular immunity☆

Abstract The addition of macrophages to cultures of PPD-stimulated lymphocytes from tuberculin-sensitive individuals results in a greater than 3-fold increase in the production of interferon over that observed in cultures of lymphocytes or macrophages alone with PPD. Polymorphonuclear leukocytes (PMN) cannot substitute for macrophages in the augmentation of interferon production. In the combined lymphocyte-macrophage cultures a dissociation in time occurs between the time of peak transformation (as measured by the incorporation of thymidine-3H) and the time of peak interferon production; peak transformation occurs at 4–6 days and peak interferon production at 7–8 days. The amount of interferon produced is related to the degree of transformation. The significance and relevance to in vivo events of this in vitro macrophage-lymphocyte interaction in the production of interferon, a mediator of cellular immunity, is discussed.

Monocyte-derived Macrophages: An in Vitro System for Studying Hereditary Lysosomal Storage Diseases

Summary: Mature macrophages obtained by the growth and differentiation of blood monocytes have been used to develop an in vitro system for the study of hereditary human lysosomal storage diseases. Maturation of monocytes into macrophages is rapid, and the maximal activities of the lysosomal hydrolases, β-galactosidase, β-glucuronidase, α-mannosidase, and β-N-acctyl glucosaminidase, is reached by the seventh day in culture. The rate of 35SO4 incorporation into mucopolysaccharides is also maximal at 7 days. Normal macrophages attain a steady state of 35SO4 labeling within 5 hr of culture and degrade about 60% of sulfated mucopolysaccharides in 5 hr. By contrast, macrophages from patients with the Hunter syndrome (MPS II), when grown in MPS II serum, degrade only 19% of sulfated MPS within 12 hr and incorporate more 35SO4 into MPS. Significant correction of the metabolic defects is achieved by incubation of the Hunter syndrome macrophages in normal serum, demonstrating that the abnormal MPS II macrophages are responsive to exogenously supplied enzyme (α-L-iduronate sulfatase). Preliminary studies of MPS turnover in macrophages from two obligate MPS heterozygotes are indicative of partially impaired MPS degradation, with increased 35SO4 incorporation and a lower rate of 35SO4-MPS degradation.Speculation: The human blood-derived macrophage system should be a useful one for the investigation of enzyme replacement and other modes of therapy for the lysosomal storage diseases.

IMMUNODEFICIENCIES, ANEUPLOIDY AND INTERFERON11This work was supported by NIH grants CA 27903, HD 15583, and GM 24309 and March of Dimes Birth Defects Foundation Grants 6-126 and 1-760.

ABSTRACT Abnormalities in production of IFN have been identified in primary and secondary immunodeficiency diseases, malignancy, in immunosuppressed patients, and patients with some congenital infections. It is not yet known whether depressed IFN production reflects absence or malfunction of a specific cell population and whether depressed IFN production contributes to the immunodeficient state, and/or is a result of the immunodeficient state. It is our opinion that therapy with IFN when defects in IFN production occur is not warranted until additional information concerning the role of IFN in the induction and pathogenesis of these diseases is obtained.