Antigenic stimulation is more efficient than LPS in inducing nitric oxide production by human mononuclear cells on the in vitro granuloma reaction in schistosomiasis

Abstract

Nitric oxide (NO) is an extremely important and versatile messenger in biological systems. It has been identified as a cytotoxic factor in the immune system, presenting anti-or pro-inflammatory properties under different circumstances. In murine monocytes and macrophages, stimuli by cytokines or lipopolysaccharide (LPS) are necessary for inducing the immunologic isoform of the enzyme responsible for the high-output production of NO, nitric oxide synthase (iNOS). With respect to human cells, however, LPS seems not to stimulate NO production in the same way. Addressing this issue, we demonstrate here that peripheral blood mononuclear cells (PBMC) obtained from schistosomiasis-infected patients and cultivated with parasite antigens in the in vitro granuloma (IVG) reaction produced more nitrite in the absence of LPS. Thus, LPS-induced nitrite levels are easily detectable, although lower than those detected only with antigenic stimulation. Concomitant addition of LPS and L-N-arginine methyl ester (L-NAME) restored the ability to produce detectable levels of nitrite, which had been lost with L-NAME treatment. In addition, LPS caused a mild decrease of the IVG reaction and its association with L-NAME was responsible for reversal of the L-NAME-exacerbating effect on the IVG reaction. These results show that LPS alone is not as good an NO inducer in human cells as it is in rodent cells or cell lines. Moreover, they provide evidence for interactions between LPS and NO inhibitors that require further investigation.

Cytokine profile, proliferation and phosphorylation of ERK1/2 and Akt in circulating mononuclear cells from individuals during the chronic intestinal phase of Schistosomiasis mansoni infection

“…NO induces a modulatory effect upon in vitro and in vivo granuloma formation. This finding suggests a protective effect related to immune response modulation [32,33]. Our data are consistent with the literature showing increased production of TNF-α after stimulation with SWAP in the supernatant of cultures from the XTO group (Figure 3A and 3F).…”

Whey protein enhances normal inflammatory responses during cutaneous wound healing in diabetic rats

“…Nitric Oxide was assayed as described by Oliveira et al [ 44 ]. Equal volumes of sulfanilamide (1.5% in 5% H 3 PO4) and naphthylethylene diamine dihydrochloride (0.1% in H 2 O) were mixed.…”

Assessment of Experimental Techniques That Facilitate Human Granuloma Formation in an In Vitro System: A Systematic Review

“…A majority of the studies were focused on mycobacteria antigens, including several mycobacterial strains such as M. tb H37Rv [ 5 , 22 , 27 , 28 , 38 , 39 , 43 , 44 , 45 , 47 , 49 , 50 , 55 , 66 , 71 , 72 , 73 , 74 , 75 , 76 ], M. tb Erdmann [ 63 , 65 , 77 , 78 ], and species such as M. leprae [ 12 , 79 ], M. abscessus [ 48 ] as well as BCG [ 24 , 29 , 30 , 56 , 57 , 62 , 69 , 80 ] and PPD [ 23 , 54 , 59 , 61 ]. Others used antigens of other infectious species such as Schistosoma [ 31 , 32 , 33 , 34 , 35 , 36 , 37 , 58 ] or Candida [ 2 , 26 , 42 , 81 ].…”