Cytomegalovirus and Epstein-Barr virus DNA transcription in endodontic symptomatic lesions.

OBJECTIVES: Productive Herpesviridae infections are implicated in the etio-pathogenesis of aggressive periodontitis. However, virtually nothing is known about a possible role of herpesviruses in pulpal and periapical pathosis. This study employed a cDNA analysis to determine transcription of human cytomegalovirus (HCMV), Epstein-Barr virus (EBV) and herpes simplex virus (HSV) in 14 recalcitrant periapical lesions and in 2 periapical healthy control sites. METHODS: Periapical samples were collected in conjunction with periapical surgery and kept frozen until virologic examination. RNA was isolated from periapical tissue by using a guanidinium isothiocyanate-acid phenol procedure (TRIZOL LS Reagent, GIBCO BRL, Rockville, MD). cDNAs were amplified by means of oligonucleotides targeting highly conserved regions of the test viruses and the RT-PCR-100 amplification kit (Sigma-Aldrich, St Louis, MO). Standardization of PCR primer sensitivity and validation was carried out according to established methods. Amplification products were identified by agarose gel electrophoresis. RESULTS: HCMV transcript was detected in 12 of 13 symptomatic and in 1 asymptomatic periapical lesion. EBV transcript was demonstrated in 8 of the 13 symptomatic lesions but not in the asymptomatic periapical lesion. HCMV and EBV dual transcription occurred at higher frequency in periapical lesions showing radiographic bone destruction of 5 mm x 7 mm or larger than in smaller size lesions (P = 0.03; Chi-squared test). No HCMV or EBV transcription was identified in the 2 healthy control sites. HSV transcript was not detected in any study site. CONCLUSION: The present data suggest that HCMV or EBV infections participate in the pathogenesis of periapical symptomatic lesions. Herpesviruses may produce periapical pathosis as a direct result of viral infection and replication, or as a consequence of virally induced impairment of the host defense and subsequent increased virulence of resident bacterial pathogens.

Histamine blocks interleukin 2 (IL-2) gene expression and regulates IL-2 receptor expression.

Histamine inhibited the proliferative response of human peripheral blood mononuclear cells (PBMC) to the T cell mitogen Phytohemagglutinin-P (PHA-P) in a dose-dependent fashion. This inhibition was mediated via the H2 receptor since cimetidine, a known H2 antagonist, removed the inhibition, whereas the addition of the H1 antagonist Diphenhydramine did not. Inhibition occurred during the inductive phase of the cell cycle, since histamine added 24 hours after PHA-P stimulation had no effect on subsequent T cell proliferation, and was attributable to inhibition of interleukin-2 (IL-2) gene expression. Both secreted IL-2 and messenger RNA coding for IL-2 were inhibited by histamine. In contrast, histamine exerted no inhibitory effect on the expression of cell surface receptors for IL-2 as determined by flow cytometry. Furthermore, histamine-treated cells retained full responsiveness to exogenously administered IL-2, which completely reversed the anti-proliferative effect of histamine. In some donors, histamine enhanced the percentage of IL-2 receptor positive cells. Stimulated PBMC from AIDS KS patients as a group, displayed a lower percentage of IL-2 receptor bearing cells, which was significantly increased by the addition of histamine even at concentrations as low as 10(-6) M and peaking at 10(-3) M. These findings indicate that histamine exerts its anti-proliferative effects on T cells by inhibiting IL-2 production, via blockade of IL-2 gene expression. In addition, histamine seems to exert immunomodulating effects on IL-2 receptor expression, particularly in those individuals with AIDS-KS.

Purification of human interleukin 2 produced from normal human peripheral blood mononuclear cells.

We have developed a simple protocol for the routine purification of essentially homogeneous human interleukin 2. The procedures applied include ammonium sulfate precipitation, ACA-54 gel filtration, ultrafiltration and chromatofocusing. The product has a molecular weight of 14 000, as determined by electrophoretic mobility, and is free of interleukin 1, interferon, granulocyte and monocyte stimulating factors, B cell growth factor and phytohemagglutinin. The method is efficient, rapid and reproduceable and provides a helpful method for preparation of IL-2 for biochemical and biological studies at moderate cost and without the use of complex equipment.

1,25-Dihydroxyvitamin D3 suppresses human T helper/inducer lymphocyte activity in vitro.

The active form of vitamin D3, 1 alpha,25-dihydroxyvitamin D3 (1,25-(OH)2-D3), suppresses in vitro immunoglobulin (Ig) production by activated peripheral blood mononuclear cells (PBM) from normal human subjects by inhibiting T helper/inducer TH cell activity. Normal PBM were fractionated into B, TH and T suppressor/cytotoxic (Ts) cells by fluorescence-activated cell sorting techniques. The resultant subsets were activated with mitogens and were cultured in the presence or absence of a receptor-saturating concentration of 1,25-(OH)2-D3. The sterol reduced [3H]thymidine incorporation in TH cells by 56%, with no effect on Ts or B cells. When 1,25-(OH)2-D3-treated TH cells were co-cultured with untreated B cells and culture supernatants assayed for Ig production, 1,25-(OH)2-D3 abrogated the inducing effect of TH cells on Ig synthesis by B cells. There was no inhibitory effect of the sterol on Ts or B cell activity. In addition, 1,25-(OH)2-D3 produced a dramatic inhibition of interleukin 2 (IL 2) production by activated PBM, but did not inhibit IL 2 receptor generation by these cells. Other vitamin D metabolites tested did not produce this effect. These results suggest that the TH lymphocyte is the specific cellular target for the immunoinhibitory effects of 1,25-(OH)2-D3.

Mediation of the antiproliferative effect of cyclosporine on human lymphocytes by blockade of interleukin 2 biosynthesis.

Normal human peripheral blood mononuclear cells (PBMC) were cultured with phytohemagglutinin-P (PHAP) and cyclosporine (CsA) to investigate the mode of action of CsA on cellular proliferation. CsA at 1 microgram/ml exerted a marked inhibitory effect on PBMC responsiveness to PHAP. An antiproliferative effect of CsA was observed at the inductive phase of the cell cycle, but the drug was ineffective when it was added to cultures 24 hr after stimulation. In parallel with this inhibitory effect interleukin 2 (IL-2) production was inhibited. In contrast, IL-2 receptor was expressed on the CsA-treated cells, and the antiproliferative influence of the drug was completely reversed by addition of highly purified human IL-2 to the CsA-treated cells. Exogenous IL-2, however, did not restore cellular capacity to produce IL-2. This study suggests that CsA acts by inhibiting IL-2 production (via blockade of IL-2 gene expression) rather than by preventing the expression of the IL-2 receptor.

Depressed interleukin 2 receptor expression in acquired immune deficiency and lymphadenopathy syndromes.

Because interleukin 2 (IL 2) production and IL 2 receptor (IL 2R) expression are essential steps in T cell proliferation, we undertook to measure these parameters, as defects in one or both seemed likely to account for the reduced proliferative response to mitogen in acquired immune deficiency syndrome (AIDS) and lymphadenopathy syndrome (LAS). Reduced proliferative responses to PHA are a well established feature of AIDS with opportunistic infection (AIDS-OI), AIDS with Kaposi's sarcoma (AIDS-KS), and LAS patient groups. IL 2R expression was significantly reduced in both AIDS groups; a similar trend was observed with the LAS group. Mean levels of IL 2 in culture supernatants for the three patient groups, however, did not significantly differ from controls. IL 2R expression was significantly correlated with proliferation and the Th:Ts ratio in the AIDS-OI and LAS groups, and a good correlation between proliferation and the Th:Ts ratio was also observed. The AIDS-KS group, in contrast, showed no significant correlations between IL 2R expression, proliferation, or Th:Ts ratio. IL 2 levels did not correlate with any of these parameters in any of the patient groups. These findings indicated that poor T cell proliferative responses to mitogen (PHA) are intrinsically related to decreased IL 2R expression in AIDS-OI and LAS. In AIDS-KS, however, a statistically significant correlational relationship between these altered immune parameters is not apparent.

Deficiency of interleukin-2 production and interleukin-2 receptor expression on peripheral blood leukocytes after phytohemagglutinin stimulation in pemphigus.

Peripheral blood mononuclear cells from 22 pemphigus patients with active disease and 30 normal subjects were evaluated for interleukin 2 (IL-2) production and IL-2 receptor expression following stimulation with phytohemagglutinin P (PHA-P). The IL-2 levels were lower in patients compared to corresponding controls and the production was delayed after PHA stimulation. This deficiency was most pronounced in severely affected patients. IL-2 receptor appearance also was lower after PHA stimulation in a small number of patients tested. These results indicate that some cellular immune functions are altered in pemphigus.

Lack of functional immunoregulatory cells in a patient with mycosis fungoides and circulating Sézary cells.

Peripheral blood lymphocytes obtained at various intervals from normal individuals and from a patient with mycosis fungoides (MF) were cultured with phytohemagglutinin (PHA) for 3 days to activate suppressor cells. After being cultured, the PHA-treated cells were irradiated, washed, and then transferred to fresh medium with PHA. The PHA responsiveness of the cells from normal individuals was suppressed approximately 90% by autologous or normal allogeneic lymphocytes activated for 3 days with PHA, whereas the cells activated for 3 days with PHA from the patient with MF lacked the capacity to inhibit the mitogenic response of autologous or allogeneic lymphocytes. These data suggest that this patient lacked suppressor T-cells that have a specificity for helper T-cells.

Structure and biological function of human IgD. XVI. T and B lymphocytes in pityriasis rosea.

The relative frequency of peripheral blood T and B cells and their biological function(s) from a group of patients with pityriasis rosea (PR) was investigated during the acute and convalescent phases of the disease using rosetting, immunofluorescent tests, and in vitro cell culturing with anti-delta and anti-mu antibodies and phytohemagglutinin (PHA). The total number of immunoglobulin (Ig) bearing cells was significantly increased, in conjunction with a slight decrease in the T cell population. Lymphocytes with surface IgD, IgM, or both Ig, accounted for the increase in the B cell population. This increase was transient, since it was only observed during the acute phase of the disease. In spite of the increase in IgD/IgM bearing B cells, the mitogenic responsiveness of B or T lymphocytes to anti-delta, anti-mu, or PHA was similar to the same patients during the convalescent phase, or to normal donors. Similarly, the levels of serum IgM, IgD, IgG, IgA and IgE in PR remained constant and at a normal concentration throughout the experimental period. The significance of the transient increase in IgD/IgM bearing cells in the pathogenesis and etiology of PR and its possible impact on the immune system is discussed.

Structure and biological functions of human IgD. XII. Anti-IgD enhancement of PHA responsiveness in patients with chronic lymphocytic leukaemia.

Specifically purifed anti-human delta stimulated the in vitro incorporation of [3H]thymidine by human peripheral lymphocytes from patients with chronic lymphocytic leukaemia (CLL). The peak response varied between individuals; those with 5--52% IgD-bearing lymphocytes exhibited maximum stimulation at 3 days, whereas a patient with only 1% IgD-bearing cells showed optimal activation at 6 days. In agreement with others, our data indicated that, in most instances, lymphocytes from patients with CLL respond poorly to PHA. One of the most important findings in this study is the enhancement of PHA responsiveness by anti-delta. Lymphocytes that exhibited reduced responsiveness to PHA alone, when pre-treated with anti-delta, showed transformation greater than the sum of the anti-delta plus PHA responses.

Structure and biological function of human IgD. IX. Anti-IgD activation of human lymphocytes.

Human peripheral lymphocytes were stimulated to incorporate tritiated thymidine when cultured with anti-sigma. The stimulation of lymphocytes by anti-sigma inversely correlates to PHA-induced lymphocyte transformation. In addition, lymphocytes from individuals with low serum IgD levels exhibited a significant response to anti-sigma, whereas, those with normal or slightly elevated levels of serum IgD showed minimal stimulation. This study is the first to provide evidence that cell surface IgD may regulate metabolic functions of lymphocytes and is consistent with the idea that IgD is a 'triggering' receptor.

Structure and biologic functions of human IgD. X. Enhancement of PHA responsiveness by anti-delta-activated lymphocytes.

Human peripheral lymphocytes with the capacity to be stimulated by anti-delta exhibited in PHA responsiveness when cultured with anti-delta 1 or 12 hr before PHA exposure over cells exposed to PHA alone. When these lymphocytes were preincubated with PHA 1 or 12 hr before anti-delta activation, no augmentation of the PHA response was seen. In addition, lymphocytes from donors with a high PHA response (low anti-delta activation) failed to show an enhancing effect on PHA responsiveness when pretreated with anti-delta. Moreover, anti-mu showed no synergistic effect on PHA responsiveness. This study is the first to indicate that anti-delta-activated cells enhance PHA responsiveness.

Cyclophosphamide-induced amelioration of Marek's disease in Marek's disease-susceptible chickens.

Bursa- and thymus-dependent functions were examined in Marek's disease (MD)-susceptible normal chickens and in chickens treated with 5 and 16 mg of cyclophosphamide (CY) at the time of hatching. Chickens not exposed to Marek's disease virus (MDV) and treated with CY temporarily lost mitogenic response to concanavalin A but regained full response after 5 weeks. Bursa-dependent functions, such as presence of germinal centers in spleen and cecal tonsils, morphologic features of bursa, and sheep red blood cell antibody response were completely lost in chickens treated with 16 mg of CY and only partly retained in chickens treated with 5 mg of CY. In chickens exposed to MDV, the degree of thymus-dependent spleen cell mitogenic response was directly related to frequency and severity of MD. Chickens treated with 16 mg of CY had a mild mitogenic depression and low frequency and severity of MD lesions, whereas those treated with 5 mg of CY and those not treated had marked mitogenic depression and high frequency and severity of MD. Suppressions of bursa- and thymus-dependent functions by MDV alone were also evident when comparing MDV-exposed and nonexposed chickens. The results also indicate that presence of small, residual amounts of humoral factor(s) may enhance MDV oncogenesis.

Synthesis of immunoglobulin and Marek's disease virus antibody in susceptible and relatively resistant chickens.

The levels of IgM, IgY, and IgA and the development of specific antibody to Marek's disease virus (MDV) and sheep red blood cells (SRBC) in young chickens susceptible and resistant to Marek's disease were compared after exposure to MDV. No significant difference was noted in the immunoglobulin levels. However, the antibody response to MDV and SRBC occurred more rapidly in susceptible birds. The initial titer of antibody to these antigens was higher. These differences in response, however, were transient. At 3 weeks post exposure, the levels of IgM antibodies to MDV and antibodies to SRBC were similar in the two lines of chickens. At 6 weeks, the levels of IgY antibodies to MDV and antibodies detected by the agar gel precipitation test were similar.

Effects of IgY antibody on the development of Marek's disease.

The effects of passive immunization with immunoglobulin Y (IgY) on the pathogenesis of Marek's disease (MD) were examined in an experimental line of White Leghorn chickens highly susceptible to MD. Purified IgY with anti-MDV antibody activity, when injected into chicks, delayed the development of MDV viremia and lesions until 9 days postinoculation (PI) with Marek's disease virus (MDV). The blastogenic response of spleen cells to concanavallin-A was depressed at 6 days PI in the birds without passive immunization, whereas it was not totally depressed until 17 days in birds passively immunized with IgY anti-MDV antibody.

Immunoglobulins and anti-Marek's disease virus antibody synthesis in chickens after passive immunization with immunoglobulin Y anti-Marek's disease virus antibody.

The effect of passive immunization with immunoglobulin Y (IgY) antibody against Marek's disease virus (MDV) was examined in MDV-susceptible chickens. The production of IgY, immunoglobulin M, and probably also immunoglobulin A was depressed in passively immunized chickens when compared with that in MDV-exposed chickens which had not been given IgY anti-MDV antibody. In passively immunized chickens, the synthesis of immunoglobulin M and IgY anti-MDV antibodies in response to MDV infection also was delayed as determined by agar gel precipitin and indirect fluorescence antibody tests.