Immunomodulatory activity of commonly used drugs on Fc-receptor-mediated human natural killer cell activation

Natural killer (NK) cells mediate defense against neoplastic as well as infected cells. Yet, how their effector functions are affected by the large variety of pharmacological compounds commonly in use has not been investigated systematically. Here, we screened 1,200 in-use or previously approved drugs for their biological effect on freshly isolated human peripheral blood-derived NK cells. Mimicking antibody-dependent cellular cytotoxicity (ADCC), known to be important in antibody-based immunotherapies against, e.g., human malignancies, the cells were stimulated by Fc-receptor (CD16) engagement. Cellular responses were assessed by flow cytometry. Fifty-six compounds that significantly inhibited and twelve that enhanced one or more of the readouts of adhesion, exocytosis, and chemokine production were identified and confirmed as hits. Among the confirmed inhibitors, 80 % could be assigned to one of seven major pharmacological classes. These classes were β2-adrenergic agonists, prostaglandins, phosphodiesterase-4 inhibitors, Ca(2+)-channel blockers, histamine H1-receptor antagonists, serotonin/dopamine receptor antagonists, and topoisomerase inhibitors that displayed distinct inhibitory patterns on NK cell responses. Among observed enhancers, interestingly, two ergosterol synthesis inhibitors were identified that specifically promoted exocytosis. In summary, these results provide a comprehensive knowledge base of the effect known drugs have on NK cells. More specifically, they provide an overview of drugs that may modulate NK cell-mediated ADCC in the context of clinical immunotherapies.

Cytotoxic response persists in subjects treated for tuberculosis decades ago

BACKGROUND

Data exploring the potential use of effector molecules produced by cytotoxic T lymphocytes (CTLs) in the immunodiagnostics of tuberculosis (TB) are scarce. The present study focused a) to gain an insight into the discriminatory power of CTLs in patients with acute pulmonary or extra-pulmonary TB, or latent tuberculosis infection (LTBI); and b) to evaluate the influence of various anti-TB therapeutic schemes on the immunological profiles of residual CTLs.

METHODS

Immunological signatures of antigen-specific CTLs were explored in patients with active pulmonary and extra-pulmonary TB, LTBI and in those treated for TB decades ago by using ELISPOT, intracellular flow cytometry and extracellular CD107a detection.

RESULTS

No difference was seen between active TB, LTBI or any of those treated for TB in the ELISPOT analysis of antigen-specific Granzyme B (GrB), Perforin (Prf) and interferon-gamma (IFN-γ) producing lymphocytes, the FACS analysis of the intracellular expression of IFN-γ, or the surface expression of CD107a degranulation factor of both CD8+ and CD4+ antigen-specific T cell subsets. The effector memory (TEM) phenotype proved predominant in the surface marker profiling both in active TB and LTBI. The proportion of the CD107a degranulation factor proved higher in the central memory (TCM) than in the other cell subsets in all the study groups. Interestingly, functionally and phenotypically similar CTLs profiles were observed in active TB, LTBI and in all the three groups treated for TB.

CONCLUSION

The phenotypic and functional profiling of CTLs has a limited potential in the immunodiagnostics of active TB. Antigen-specific CTLs persist in patients treated for TB decades ago regardless of the efficacy of implemented and completed anti-TB therapy.

CD3 expression distinguishes two gammadeltaT cell receptor subsets with different phenotype and effector function in tuberculous pleurisy

Tuberculous pleurisy is a naturally occurring site of Mycobacterium tuberculosis (Mtb) infection. Herein, we describe the expression of activation, natural killer (NK) and cell migration markers, as well as effector functions from gammadeltaT cells in peripheral blood (PB) and pleural effusion (PE) from tuberculosis patients (TB). We observed a decreased percentage of circulating gammadeltaT from TB patients and differential expression of NK as well as of chemokine receptors on PB and PE. Two subsets of gammadeltaT cells were differentiated by the CD3/gammadeltaT cell receptor (gammadeltaTCR) complex. The gammadeltaTCR(low) subset had a higher CD3 to TCR ratio and was enriched in Vdelta2(+) cells, whereas most Vdelta1(+) cells belonged to the gammadeltaTCR(high) subset. In PB from TB, most gammadeltaTCR(high) were CD45RA(+)CCR7(-) and gammadeltaTCR(low) were CD45RA(+/-)CCR7(+)CXCR3(+). In the pleural space the proportion of CD45RA(-)CCR7(+)CXCR3(+) cells was higher. Neither spontaneous nor Mtb-induced interferon (IFN)-gamma production was observed in PB-gammadeltaT cells from TB; however, PE-gammadeltaT cells showed a strong response. Both PB- and PE-gammadelta T cells expressed surface CD107a upon stimulation with Mtb. Notably, PE-gammadeltaTCR(low) cells were the most potent effector cells. Thus, gammadeltaT cells from PB would acquire a further activated phenotype within the site of Mtb infection and exert full effector functions. As gammadeltaT cells produce IFN-gamma within the pleural space, they would be expected to play a beneficial role in tuberculous pleurisy by helping to maintain a T helper type 1 profile.

Flow cytometric detection of degranulation reveals phenotypic heterogeneity of degranulating CMV-specific CD8+ T lymphocytes in rhesus macaques

Flow-cytometric conditions for detection of lysosomal-associated membrane proteins (LAMPs) on the surface of recently degranulated cells were optimized for rhesus macaques and used to investigate the functional properties of rhesus cytomegalovirus (rhCMV)-specific CD8+ T lymphocytes with regards to cytotoxicity and interferon (IFN)-gamma secretion in six asymptomatic CMV-seropositive rhesus macaques. Unlike humans, the rhesus macaque LAMP-1 protein CD107a underwent little or no endocytosis over a six to 18 h stimulation period. Following in vitro stimulation, rhCMV-specific CD8+ T lymphocytes were heterogeneous with regards to the composition of cells positive for CD107a and/or IFN-gamma, time to reach peak degranulation, and kinetics of IFN-gamma secretion relative to degranulation. Responder CD8+ T lymphocytes that underwent degranulation without IFN-gamma production (CD107a+IFN-gamma-) were predominantly composed of terminally differentiated effectors (CD28-CD45RA+). Moreover, they had significantly lower frequencies of effector memory (CD28-CD45RA-) cells compared to the IFN-gamma-secreting cells that did or did not undergo degranulation (CD107a+IFN-gamma+ or CD107a-IFN-gamma+). The perforin content of effector CD8+ T lymphocytes was significantly greater than that of effector memory CD8+ T lymphocytes in rhesus macaques, suggesting that they were more cytolytic. Our findings suggest that the composition of rhCMV-specific CD8+ T lymphocytes with regards to CD107a+IFN-gamma- responders may be an important determinant of their ability to control CMV replication.

Functional profile of human influenza virus-specific cytotoxic T lymphocyte activity is influenced by interleukin-2 concentration and epitope specificity

The ability of influenza A virus-specific cytotoxic T lymphocytes (CTL) to degranulate and produce cytokines upon antigenic restimulation was studied in four HLA-A*0101 and HLA-A*0201 positive subjects. Peripheral blood mononuclear cells of these subjects were stimulated with influenza A virus in the presence of high or low interleukin (IL)-2 concentrations. CD8(+) T cell populations specific for the HLA-A*0101 restricted epitope NP(44-52) and the HLA-A*0201 restricted epitope M1(58-66) were identified by positive staining with tetramers of peptide major histocompatibility complexes (MHC) (NP-Tm and M1-Tm, respectively). Within these populations, the proportion of cells mobilizing CD107a, or expressing interferon (IFN)-gamma and tumour necrosis factor-(TNF)-alpha upon short-term peptide restimulation was determined by flow cytometry. Independent of IL-2 concentrations, large subject-dependent differences in the mobilization of CD107a and expression of IFN-gamma and TNF-alpha by both NP- and M1-specific T cells were observed. In two of the four subjects, the functional profile of NP-Tm(+) and M1-Tm(+) cells differed considerably. Overall, no difference in the proportion of NP-Tm(+) or M1-Tm(+) cells expressing CD107a was observed. The proportion of M1-Tm(+) cells that produced IFN-gamma (P < 0.05) was larger than for NP-Tm(+) cells, independent of IL-2 concentration. When cultured under IL-2(hi) concentrations higher TNF-alpha expression was also observed in M1-Tm(+) cells (P < 0.05). The IL-2 concentration during expansion of virus-specific cells had a profound effect on the functionality of both M1-Tm(+) and NP-Tm(+) cells.