Donor Macrophages Research Articles

Chemokine receptor regulation and HIV type 1 tropism in monocyte-macrophages.

Monocyte-macrophages can be productively infected by CCR5-specific, but not CXCR4-specific, HIV-1. This could be due either to the absence of this chemokine receptor in this cell lineage or to other, yet undefined cellular cofactors that modulate the coreceptor activity of the CXCR4 in these cells. To investigate the basis of macrophage tropism, we studied the expression of CCR5 and CXCR4, as well as several of the other CC chemokine receptors, on monocyte-macrophages at different stages of differentiation. We found that on fresh monocytes, CXCR4 was relatively abundant, but it fell to barely detectable levels in culture over 24 hr and maintained this low level of expression during differentiation in vitro. Some donor macrophages appeared to express CXCR4 at levels comparable to CCR5. In contrast, CCR5 expression was low on fresh monocytes but increased on in vitro differentiation. Taken together, the results show that monocyte-macrophage differentiation is associated with a differential expression of chemokine receptors that may contribute to, but does not fully account for, the selectivity of these cells to HIV entry. GM-CSF, a cytokine that induces macrophage differentiation, caused a rapid decrease in CXCR4 and CCR5 mRNA and was correlated with decreased ability to support HIV entry.

Dynamics of monocytes/macrophages and T lymphocytes in acutely rejecting rat renal allografts.

We examined the infiltration of acutely rejecting renal allografts (DA-->LEW) by ED1+ and ED2+ macrophages and T lymphocytes at intervals of 24 h after transplantation. Donor and recipient macrophages were differentiated by MHC class II antigen expression in double-staining experiments with ED1. Proliferation was assayed after pulse-labelling with BrdU. We subdivided allograft infiltration into three consecutive phases: 1) During phase I on days 1 to 2 after allogeneic kidney transplantation, perivascular infiltrates developed that contained numerous donor and recipient macrophages. Allograft rejection could already be diagnosed 24 h after transplantation by perivascular infiltration of T lymphocytes, whereas T cells were rarely found in isografts. 2) Phase II of allograft rejection from day 3 to 4 was characterized by massive propagation of the infiltrate. About equal numbers of interstitial donor and recipient macrophages were counted. Both macrophages and T lymphocytes proliferated in situ and macrophages outnumbered T cells until complete rejection. 3) During phase III the allograft was destroyed. Large intravascular monocytes surprisingly expressed the ED2 antigen. In the interstitium of viable graft regions, the population of recipient macrophages grew, whereas the population of donor macrophages and of T lymphocytes decreased.

The growth kinetics of intracellular bacille Calmette-Guerin (BCG) within human monocyte-derived macrophages of different ethnic populations.

In this paper we have examined intracellular mycobacterial growth in human monocyte-derived macrophage cell cultures. Cells from three population groups were selected to compare and contrast the kinetics of intracellular BCG growth both by determining changes in metabolic activity of dividing bacteria by radio-isotope incorporation and growth/survival by estimating colony forming unit by Fazal's Microcolony Counting Method. These data indicate that BCG infects and multiplies intracellularly in human macrophages and may serve as an in vitro model for studying inherent capability of mycobacteria to grow and infect macrophage populations. There is however, no inhibition or reduction of intracellular mycobacterial growth from a Caucasian male and female, and an Afrocarribean female donor macrophages. On the contrary, there is a ten-fold increase in the replication of mycobacteria over a 7-day infection period. Patterns of BCG growth within macrophage cultures from different donors were determined and variation calculated at different days post-infection. Experiment to experiment coefficient of variation of intracellular BCG growth estimates for a single donor is between 4-12%. In contrast, the coefficient of variation of intracellular BCG growth between three different macrophage donors studied is < 4%.

The relationship between AIDS dementia complex and the presence of macrophage tropic and non syncytium inducing isolates of human immunodeficiency virus type 1 in the cerebrospinal fluid

We sought to determine the clinical significance of macrophage tropic and non-syncytium inducing isolates of human immunodeficiency virus type 1 (HIV-1) in the cerebrospinal fluid (CSF) of patients with and without AIDS dementia complex (ADC). HIV-1 was isolated from the CSF of 31 patients with and without ADC. The isolates were then characterised as to the degree of macrophage tropism by quantitation of p24 production and the presence of syncytium inducing (SI) or non-syncytium inducing (NSI) isolates by MT2 assay and SupT1 coculture. The degree of macrophage tropism varied according to the donor macrophage that was used except in strongly macrophage tropic isolates. Moderate and severe ADC (stage > or = 2) was associated with the presence of highly macrophage tropic isolates in the CSF (P = 0.01). The sensitivity and specificity values of a highly macrophage tropic isolate in the CSF for ADC stage > or = 2 were 82% and 66% respectively while the predictive value was 64%. Three of four asymptomatic patients with such highly macrophage tropic isolates in the CSF subsequently developed ADC after an average of 4 months. Twenty-eight isolates from the CSF and 23 from the blood were NSI regardless of the presence or absence of ADC. The predictive value of an SI isolate in the blood reflecting an SI isolate in the CSF was 37.5% while the predictive value of an NSI isolate in the blood reflecting an NSI in the CSF was 100%. These data suggest that host factors are essential in determining the degree of macrophage tropism in HIV-1 and that such tropism is important for the presence and possibly subsequent development of ADC. The CSF usually has NSI isolates regardless of the presence of ADC and irrespective of the presence of such isolates in the blood thereby suggesting that the CSF is behaving virologically as a separate compartment to the blood.

Suppressor macrophages in Trypanosoma brucei infection: nitric oxide is related to both suppressive activity and lifespan in vivo

African trypanosome infections cause immunosuppression in both experimental rodent and natural hosts. One characteristic of this is an eliciting of suppressor macrophages which results in an unresponsiveness in lymphocytes. Macrophages from Trypanosoma brucei-infected mice have previously been shown to produce high levels of nitric oxide (NO). Using model systems based on in vivo macrophage transfer and drug cure, we have sought to determine the relationship between NO and suppressed lymphocyte responses. Peritoneal macrophages from T. brucei-infected mice inhibited the Concanavalin A (Con-A) response of spleen cells from syngeneic recipients 3-4 days after transfer in vivo due to the activity of suppressor macrophages. When macrophage NO synthesis was inhibited either in vitro or in vivo the suppressive effects were partially abrogated. These data provide evidence of a role for NO in mediating immunosuppression during murine T. brucei infection. Suppression in spleens of mice receiving suppressor macrophages was transient, with total recovery of spleen cell mitogen responses six days after transfer. Suppression and recovery was found to coincide with the presence or absence (respectively) of donor macrophages in recipient spleens. When T. brucei-infected mice were treated with a curative dose of a trypanocide there followed a recovery of lymphocyte responsiveness after a period of 4-5 days, and this directly correlated with a reduction of macrophage NO synthesis to control levels both in vivo and in vitro. The apparent loss of suppressor macrophage activity after 4-6 days in both drug cured animals and recipients of macrophage transfer was shown to be due to NO-mediated apoptosis of these cells.

The magnitude of HIV replication in monocytes and macrophages is influenced by environmental conditions, viral strain, and host cells.

It has been difficult to standardize the effects of various stimuli on HIV replication in monocytes and macrophages in different laboratories. In this study we have shown that it is possible to standardize HIV inocula, culture conditions, and HIV antigen assay to achieve reproducibility with the same viral isolate and donor monocyte and macrophage. However, changes in serum concentration, in the strain of blood-derived isolate (even at low passage), in the donor source of the monocyte/macrophage, and in the state of cellular maturation all influenced HIV production by these cells. The donor source of monocytes contributed as much to variability in HIV production as the HIV strain and results were reproducible when the same source was used repeatedly. These in vitro data suggest that genetic differences may contribute to differences in HIV replication in macrophages and consequently to tissue virus load in vivo.

MORPHOMETRIC ANALYSIS OF INFILTRATING CELLS THAT ADHERE TO THE SINUSOIDAL WALL AND MIGRATE INTO THE SPACE OF DISSE IN THE ORTHOTOPICALLY TRANSPLANTED RAT LIVER

To reveal the kinetics of infiltrating cells in the hepatic parenchyma after the liver transplantation, we identified the cell type (macrophages, monocytes, agranular lymphocytes, large granular lymphocytes, and neutrophils) and localization on toluidine blue-stained sections of perfusion-fixed liver grafts in rejecting and tolerant combinations and performed quantitative analysis of the density of each cell species infiltrating inside and outside the sinusoid at days 4 and 7. The number of total infiltrating cells per unit square became 9 times as high as that of an untreated liver at day 4 and 30 times as high at day 7. Macrophages accounted for a large part of the infiltrating cells both in and around the sinusoid: 72% of intrasinusoidal infiltrating cells and 88% of extrasinusoidal ones at day 4; 73% of intrasinusoidal ones and 93% of extrasinusoidal ones at day 7. The ratio of extrasinusoidal cell to intrasinusoidal cell of macrophages was 9:91 at day 4 and 34:66 at day 7, much higher than ratios of other infiltrating cells. This fact means that macrophages show a marked tendency to migrate out of the sinusoid in the liver graft. The proportion of macrophages to total infiltrating cells dropped at day 4 and went up again at day 7, while that of monocytes showed a reverse pattern. Histologically, immature macrophages, possibly derived from recipient monocytes, coexisted with vacuolated donor macrophages in the sinusoid at day 4, but the latter cells were diminished at day 7. These data indicate that transformation of recipient monocytes into macrophages in the sinusoid and subsequent extrasinusoidal migration of newly formed macrophages occur soon after the cell influx into the liver graft begins at day 4. The present study has revealed that macrophages, especially those migrating into the space of Disse, will be closely related to the pathogenesis of the liver transplantation.

Cell Contact and Direct Transfer Between Co-Cultured Macrophages and Fibroblasts

Mouse peritoneal macrophages formed attachments with beta-glucuronidase deficient human fibroblasts within an hour after co-cultures were initiated. Some of these attachments were transitory, while in others macrophages remained in firm contact with fibroblasts for many hours. Attachment of one macrophage did not prevent attachment of others, since many fibroblasts made firm contact with four or five other cells. Not all macrophages, however, attached themselves to fibroblasts. Macrophages injected with Lucifer yellow did not transfer the dye to fibroblasts with which they had made contact, nor was there any reverse transfer from injected fibroblasts to macrophages. Lucifer yellow was, however, transferred rapidly from injected fibroblasts to other adjacent fibroblasts with which they had formed gap junctions. Macrophages whose lysosomes had been pre-loaded with FITC-dextran did transfer this ligand to recipient fibroblasts, where it became localised in a perinuclear pattern with many bright punctate patches adjacent to donor macrophages. Transfer of FITC-dextran was blocked when cells were separated by nucleopore membranes in an analogous manner to transfer of endogenous lysosomal beta-glucuronidase.

Particulate antigens may be reprocessed after initial phagocytosis for presentation to T cells in vivo.

Macrophages were pulsed with Listeria monocytogenes antigens by intraperitoneal injection prior to harvesting and thoroughly washing the cells. The pulsed macrophages were injected into the feet of Listeria-immune or naive mice to elicit a delayed hypersensitivity reaction. Where soluble Listeria antigen was used, presentation by donor macrophages to host T cells required identity within the I region of the H-2 complex. However, presentation of alcohol-killed Listeria organisms or of a living, temperature-sensitive mutant of Listeria was apparently not H-2 restricted. When T cells enriched in vitro for Listeria reactivity were injected into the feet of naive mice, they reacted in an H-2 restricted manner to antigen presented to them either by the pulsed macrophages or host cells apparently acquiring antigen from the original pulsed macrophages.

MAJOR HISTOCOMPATIBILITY COMPLEX RESTRICTION AND

Studies of the survival of weakly histoincompatible skin grafts in which the Langerhans' cells (LC)5 have been replaced with major histocompatibility complex (MHC)-compatible or incompatible LC, as well as studies of the fate of cultured endocrine allografts in MHC-compatible and incompatible mice and rats, indicate that allografts are only recognized as foreign if they possess donor macrophages (or cells of this family), or if antigen presenting cells MHC-compatible with the graft can be provided by the host.

Influence of culturing on the functioning of major-histocompatibility-complex-compatible and incompatible islet grafts in diabetic mice.

Culturing B10.BR (H-2k) islets promotes their survival in major histocompatibility complex (MHC)-incompatible BALB/c (H-2d) mice, but not in MHC-compatible CBA (H-2k) animals. These results provide further evidence that MHC restriction is involved in transplantation immunity--i.e., that allografts are only recognized as foreign if they possess donor macrophages (or cells of this family), or if antigen-presenting cells MHC-compatible with the graft can be provided by the host.

Evidence for major histocompatibility complex restriction in transplantation immunity.

Studies on the survival of histocompatibility-Y antigen (H-Y)-incompatible and skin-specific antigen (Skn)-incompatible skin grafts in mice, as well as those concerned with the survival of cultured parathyroid allografts in rats, indicate that grafts provoke a strong immune response only if they include donor macrophages (or Langerhans cells) or if major histocompatibility complex-compatible macrophages are available to react with cells bearing the foreign antigens.

Genetically determined susceptibility to Leishmania tropica infection is expressed by haematopoietic donor cells in mouse radiation chimaeras.

Models of the different disease patterns of cutaneous leishmaniasis can be established by infecting various inbred strains of mice with Leishmania tropica. The BALB/c strain is exceptionally susceptible in that the infection is dosage independent and inexorably progressive, terminating in cutaneous and fatal visceral metastasis1–3. This is largely determined by a single autosomal non-H–2-linked gene3, seemingly not identical to the well-characterized Lsh gene which determines innate susceptibility to systemic Leishmania donovani infection4,5. Although H–2-linked genetic influences are also detectable in the immune stage of both leishmanial infections3,6, they are relatively minor in the case of L. tropica. Thus, although progression of disease induced by lower infecting doses is slower in congeneic B ALB/K (H–2k) than in BALB/c or BALB/B (H–2b) mice, the eventual outcome is similar in all three3. This inability to control L. tropica infection seems to involve profound impairment of potentially curative cell-mediated immunity by the generation of a specific suppressor T-cell population7. With two other pathogens which infect mononuclear phagocytes, Listeria monocytogenes and Mycobacterium iepraemurium, differences in mouse strain susceptibility have been attributed to extrinsic factors regulating macrophage activity rather than to intrinsic gene expression within the cells themselves8,9. The relative strain susceptibility of mice to myxoviruses (determined by the dominant allele Mx) is also a genetic characteristic of their macrophages in vitro10. Nevertheless, radiation chimaeras exhibit the myxovirus resistance profile of the host despite near-total haematopoietic cell replacement, including donor macrophages which can still express their original susceptibility in vitro11. In contrast, the experiments described here indicate unequivocally that susceptibility to L. tropica in radiation chimaeras compatible at the major histocompatibility (H–2) locus is determined by the descendants of donor haematopoietic cells and not by host environmental factors.

Action of a cytotoxin from the venom of a central asiatic cobra on rat liver mitochondrial function

The blood serum of patients with active tuberculosis of the lungs and chronic pneumonia inhibited migration of donor's leukocytes and macrophages of the peritonal exudate of guinea pigs when compared with migration of similar cells in the medium with the serum of cattle or donors. After chromatography these sera were fractionated on the columns with Sephadex G-100. Fractions containing the leukocyte migration inhibition factor (LMIF) suppressed, up to complete abolition, the intradermal reaction to tuberculin in man and guinea pigs sensitized with BCG. The LMIF is supposed to act in the regulation of delayed hypersensitivity reaction.

Passive transfer of immunity to typhoid by macrophages.

Saito, Kazuhisa (Keio University School of Medicine, Tokyo, Japan), Masayasu Nakano, Takehisa Akiyama, and Daizo Ushiba. Passive transfer of immunity to typhoid by macrophages. J. Bacteriol. 84:500-507. 1962.-Cultured peritoneal macrophages collected from mice which had been injected intravenously with intact macrophages of mice immunized with live vaccine were found to exert inhibitory action against intracellular virulent Salmonella enteritidis. This inhibition was quantitatively inferior to that exhibited by peritoneal macrophages from the donors, i.e., mice actively immunized with live vaccine. After an intravenous injection of P(32)-labeled macrophages into mice, almost no radioactivity could be recovered in the peritoneal exudate cells of the recipients; about 50% of the radioactivity was recovered from the liver, spleen, and mesenteric lymph nodes. Therefore, the inhibitory action of the recipient's peritoneal macrophages against intracellular multiplication was attributed to the capacity of the recipient's own macrophages and not to that of the donor's macrophages. Tissue-cultured macrophages from recipients of sonic-treated cells did not exhibit inhibition against intracellular, virulent S. enteritidis, although the recipients were resistant to intraperitoneal infection with the same strain.