Regulation of natural killer cell activity by macrophages in the rheumatoid joint and peripheral blood

Recently, in another study, we observed that indomethacin, a prostaglandin synthetase inhibitor, significantly increased NK activity in both normal and rheumatoid arthritis (RA) peripheral blood (PB) but not in RA synovial fluid (SF). Because macrophages are a major source of prostaglandins, we examined the effect of macrophage-enriched adherent cells (AC) on NK activity as measured by a 3-hr Cr-release assay with K 562 cells. The removal of AC resulted in increased (p less than 0.01) NK activity in both normal and RA PB. In contrast, the removal of AC from RA SF resulted in a significant decrease (p less than 0.001) of NK activity. By using only nonadherent cells (NAC), NK activity in RA SF and synovial tissue (ST) was significantly reduced when compared to autologous RA PB (p less than 0.001). Enhancement of NK activity of SF NAC by both poly I:C and IL 2 was not dependent on AC. Mixing experiments demonstrated that the addition of synovial AC for 16 hr increased NK activity of synovial NAC to a level similar to that of unseparated mononuclear cells, whereas autologous PB AC suppressed NK activity of PB NAC. PB AC, when added to SF NAC, also increased NK activity. Supernatants from synovial mononuclear cells were stimulatory of synovial NAC NK activity, whereas normal PB mononuclear supernatants were suppressive. These observations document 1) a significant reduction of NAC-mediated NK activity in the rheumatoid joint as compared to PB from the same patient, and 2) that AC modulate NK activity differently in the rheumatoid joint as compared to RA or normal PB.     

Effects of short-term administration of sex hormones on normal and autoimmune mice

The effects of short-term administration (2 to 4 wk) of sex hormones on the immune system of normal (C57BL/6) and autoimmune (C57BL/6-lpr, C3H/lpr, B/W) strains of mice were investigated. Both estrogen (E2) and testosterone (Te) had significant effects on the numbers of T and B cells as well as on the density of cell surface antigens as demonstrated by flow cytometry. For example, Te depleted Thy-1.2+ thymocytes in normal mice and brought about a shift to lower density cells. Lyt-2+ cells appeared to be the main target cells of hormonal modulation in normal and autoimmune mice. Both sex hormones significantly depleted these cells in the thymus but had differential effects in the peripheral lymphoid organs, particularly in the spleen. In general, E2 depleted Lyt-2+ cells, whereas Te increased or maintained this subpopulation of cells in spleen and lymph nodes. Similarly, the suppressor cell activity and IL 2 production on a per cell basis in E2-treated animals was diminished, whereas Te-treated animals had normal or enhanced activity. The relevance of these findings to differential sex susceptibility in autoimmune diseases is discussed.     

VH sequence of a human anti-Sm autoantibody. Evidence that autoantibodies can be unmutated copies of germline genes

The utilization of germline genes for the synthesis of autoantibodies has been suspected for many years based on the presence of cross-reactive idiotypes among patients as well as in some healthy first-degree relatives of patients with several autoimmune diseases including SLE. One such system of idiotypes involves anti-Sm antibodies, which are highly specific for SLE. To definitively establish the utilization of germline genes in the Sm system, we produced human-human B cell hybridomas from a patient with SLE who had circulating anti-Sm antibodies. One stable hybridoma designated 4B4 secretes an IgM-kappa mAb that binds Sm and shares idiotypic determinants with other anti-Sm antibodies. A second anti-Sm antibody (3C3), isolated from the same patient was also studied. Oligo(dT) priming was used to produce cDNA corresponding to full length IgM. Sequence analysis revealed that the VH gene segment (1-96) of 4B4 is identical to a VH sequence previously detected in a fetal liver cDNA library by Schroeder and his co-workers as well as a germline VH recently described by Berman and his associates. The identity of a lupus mAb and sequences derived from unrelated individuals provides strong evidence that this autoantibody is a direct copy of a germline gene.     

Ig VH gene family repertoire of plasma cells derived from lupus-prone MRL/lpr and MRL/++ mice

VH gene family usage was determined in both spontaneous, in vivo activated plasma cells and LPS-induced plasma cells from individual MRL/lpr mice by using in situ hybridization. It was found that VH gene family expression in spontaneous plasma cells varied from mouse to mouse. Some mice expressed VH families in an apparently random manner similar to that obtained with polyclonal activation. Other mice showed an exaggerated expression of particular VH gene families. VH J558 was overrepresented most frequently, but overrepresentation of VH 7183, Q52, and 36-60 was also observed. Importantly, LPS-induced VH gene family expression in these same mice displaying biased VH family usage in spontaneous plasma cells, appeared normal with no evidence for similar biases in the LPS-induced repertoire. Anti-DNA antibody concentrations and the degree of glomerulonephritis were determined for each mouse to measure the severity of disease. The level of expression of the J558 family was positively correlated with disease severity. The results suggest that the initial autoantibody response is highly diverse but becomes more restricted as the disease progresses.     

Natural killing in estrogen-treated mice responds poorly to poly I.C despite normal stimulation of circulating interferon.

Natural killing by mouse spleen cells can be stimulated in vivo by interferon or by agents that stimulate interferon, such as poly I.C. Natural killing can be suppressed in vivo by the sustained administration of 17 beta-estradiol. In BALB/c mice that had been treated with 17 beta-estradiol for 10 weeks, natural killing did not respond to intravenous poly I.C, although stimulation of circulating interferon was equal to controls. Estradiol, then, does not block interferon production but does suppress the response of natural killer cells to interferon. It is suggested that estrogens either block the maturation of natural killer cells or reduce the number of natural killer cell precursors.     

Association of neuronal pp60c-src with growth cone glycoproteins of rat brain

Tyrosine phosphorylation and protein tyrosine kinase (PTK) activity in the growth cone membrane-associated glycoprotein (GCGP) fraction of 1-day-old rat brain were examined. Using immunoblotting and immunoprecipitation techniques, pp60^c-src was identified as one of the major PTKs associated with GCGPs. Furthermore, only GCGP-associated src that was also tyrosine phosphorylated was active. Immunoprecipitation experiments using various src antibodies revealed that pp60^c-src contributed partially to the PTK activity detected in GCGPs, and that it is associated with several proteins of Mr 140 K, 120 K, 85 K and 50 K. This association of src protein with GCGPs was specific, and another src family member p59^fyn, which is also abundant in the brain, did not exhibit such an association. In addition to pp60^c-src, the GCGP fraction contained several major phosphotryosine-containing proteins of Mr 140 K, and a 97/90 K doublet that corresponded to the beta subunits of IGF-I/ insulin receptors. These studies show that pp60^c-src associated with GCGPs is an active PTK that could be involved in neuronal growth and development, transmembrane signalling, and in recognition and/or adhesive events. © 1992 John Wiley & Sons, Inc.     

Interleukin 2 deficiency is a common feature of autoimmune mice

IL 2 production was studied in autoimmune mice to assess the role of this lymphokine in the pathogenesis of murine lupus. Spleen and lymph node cells from autoimmune-susceptible mice show an age-dependent loss in the ability to produce functional IL 2. This defect correlates with disease expression and is most severe in MLR/Mp-Ipr/Ipr mice. MLR/Mp-Ipr/Ipr thymocytes gradually lose responsiveness to IL 2 with age. These results suggest that the immunoregulatory abnormalities of autoimmune mice may be due in part to IL 2 deficiency.     

Assessment of eye doses to staff involved in interventional cardiology procedures in Kuwait

In this study, which is the first of its kind in the gulf region, eye doses of interventional cardiologists and nurses were measured using active dosimeters for left and right eyes, in 60 percutaneous coronary interventions in three main hospitals in Kuwait. The dose given in terms of H_p(0.07) per procedure when ceiling suspended screens were used by main operators ranged from 18.5 to 30.3 µSv for the left eye and from 12.6 to 23.6 µSv for the right eye. Taking into account typical staff workload, the results show that the dose limit of 20 mSv/year to the eyes can be exceeded for interventional cardiologists in some situations, which demonstrates the need of using additional effective radiation protection tools, e.g. protective eye spectacles, in addition to the regular and proper use of ceiling suspended screens. With indications of increase in workload, the need for availability of a dedicated active dosimeter for the regular monitoring of eye doses is emphasized.