Tsuyoshi Igarashi

Mechanisms of age-related decline in antigen-specific T cell proliferative response: IL-2 receptor expression and recombinant IL-2 induced proliferative response of purified Tac-positive T cells

Proliferative response of T cells from aged persons was significantly reduced to a specific antigen tuberculin-active peptide (TAP) determined by [3H]TdR uptake and FCM in comparison to that from the young. Cytokinetic analysis for the proliferative response to TAP showed that, in the aged, the clonal size or the number of the first generation responding cells to TAP was not significantly reduced but the ability to repeat replication was more profoundly affected. Neither the delayed entry into the cell replication nor prolongation of the cell cycle time could explain these results. Similar results have been reported on the proliferative response of T cells to mitogen: PHA (Phytohemagglutinin). Expression of Tac-antigen on T cells determined by anti-Tac antibody binding with FACS after stimulation with either TAP or PHA was found to be reduced significantly in the aged. Both the numbers of high and low affinity IL-2 receptors determined by radiolabelled IL-2 binding assay were also reduced in the aged, but the degree of reduction in number of high affinity ones was more pronounced than that in low affinity ones. Tac-positive T cells were isolated with the use of anti-Tac rosette methods and stimulated with recombinant IL-2 (r-IL-2). Their proliferative response was significantly lower in the aged than that in the young at any concentration of r-IL-2 examined. The number of the first generation responding cells to r-IL-2 in purified Tac-positive T cells from the aged was 82% of that from the young whereas the proliferative response by aged T cells was 39% of that by young ones when the cells were allowed to repeat replication for 3 days. The mechanisms of these multifactorial defects in proliferation of T cells from aged persons were discussed.

Age-associated changes in proliferative and differentiative response of human B cells and production of T cell-derived factors regulating B cell functions

The abilities of highly purified B cells to repeat replication for clonal expansion and to differentiate into immunoglobulin secreting cells (ISC) were examined in the aged and young groups. B cells from the aged showed twofold less proliferative response to B cell mitogen Cowan 1 (SAC) than those from the young. The original clone size of SAC responding B cells determined by colchicine block and [3H] thymidine [( 3H] TdR) uptake was not significantly reduced in the aged whereas the ability to repeat replication to expand clonal size was significantly reduced. B cells from aged and young persons were induced into ISC by combined stimulation with SAC and partially purified B cell differentiation factor (BCDF) free of IL-2 activity. ISCs for IgG and IgA were rather increased or at least not reduced in number in the aged as compared with those in the young. We also determined the IL-2 and BCDF activity produced by T cells from aged and young persons. Upon PHA stimulation, the aged T cells produced tenfold less IL-2 activity and threefold higher BCDF activity than did young T cells. Approximately threefold increase in spontaneous secretion of BCDF activity by aged T cells was found as compared with young T cells. The inverse correlation between the IL-2 activity and BCDF activity was found when both activities were determined in the same samples.

Immune Responses to Polyethylene Glycol Modified L-Asparaginase in Mice

Suppression of anti-L-asparaginase (anti-A-ase) IgG and IgE antibody responses was achieved in Balb/c mice with polyethylene glycol (PEG, MW, 5,000) conjugated Escherichia coli A-ase. Following the administration of the mixture of A-ase and PEG-A-ase, antibody production to A-ase was reduced. PEG-A-ase administration prior to A-ase suppressed the primary and secondary responses to A-ase antibody. The suppression could be transferred to normal mice with spleen cells from A-ase tolerant mice. The cell transfer experiment showed that the suppression was caused by suppressor T cells. Since PEG-A-ase administration failed to suppress antibody response to ovalbumin, the suppression seemed to be A-ase specific. PEG-A-ase administration also suppressed the delayed type hypersensitivity reaction. IgG and IgE antibodies to PEG or PEG-A-ase were not detected in mice immunized with PEG or PEG-A-ase in the presence of Freunds complete adjuvant or A1(OH)3, respectively.

The association of Pro12Ala polymorphism in PPARγ2 with lower carotid artery IMT in Japanese

In this study, the association of the Pro12Ala peroxisome proliferator-activated receptor gamma2 (PPARgamma2) polymorphism with atherosclerosis was examined in a Japanese Type 2 diabetic population. PPARgamma has been identified as a key regulator of adipogenesis. Recently, some studies reported that the Pro12Ala polymorphism was associated with resistance to Type 2 diabetes. It is well-known that Type 2 diabetes is closely related with disorder of lipid metabolism as well as impaired glucose homeostasis, resulting in atherosclerosis. We aimed to evaluate the association between carriers of the Pro12Ala PPARgamma2 mutation and clinical profiles concerning atherosclerosis besides plasma glucose and lipid concentrations. Screening for the mutation was performed using the polymerase chain reaction-restriction fragment length polymorphism (PCR-RFLP) method among 154 Type 2 diabetic patients. The homozygotes of the Pro12 allele were 143 (93%), the heterozygotes of the Pro12 and Ala12 allele were 11 (7%) and the homozygote of the Ala12 allele was not detected. The group with the Ala12 allele had a significantly lower value of carotid artery intima-media thickness (IMT) than that without it, although there was no difference between two groups in sex, age or other clinical variables we examined. The Pro12Ala PPARgamma2 polymorphism may be associated with carotid artery IMT values in Type 2 diabetes mellitus.

Adjuvant activity of synthetic N-acetylmuramyl-l-alanyl-d-isoglutamine and related compounds on cell-mediated cytotoxicity in syngeneic mice

Abstract Cell-mediated cytotoxicity against syngeneic P815-X2 mastocytoma cells was induced by the in vitro secondary stimulation of DBA/2 spleen cells from animals immunized with mitomycin C-treated P81S-X2 cells. Adjuvant activity of BCG cell-wall skeleton (BCG-CWS), and synthetic N -acetylmuramyl- l -alanyl- d -isoglutamine and its analogs was examined in this in vitro secondary cytotoxic response against weakly immunogenic tumor cells. BCG-CWS, N -acetylmuramyl- l -alanyl- d -isoglutamine, and 6- O -mycoloyl- N -acetylmuramyl- l -alanyl- d -isoglutamine demonstrated significant adjuvant activity. Substitution of l -alanine of the synthetic adjuvants by glycine seemed to reduce the adjuvant activity.

Association of plasma PAF acetylhydrolase gene polymorphism with IMT of carotid arteries in Japanese type 2 diabetic patients

The aim of this study was to investigate association of a missense mutation in plasma PAF acetylhydrolase (G994T) with intima media thickness (IMT) of the carotid arteries. One hundred and forty Japanese type 2 diabetic patients aged from 40 to 79 years without severe nephropathy were enrolled in this study. The genotype of the patients was determined by allele specific PCR. IMT of the carotid arteries of the subjects was recorded by B-mode ultrasound imaging. The patients were divided into two groups by genotyping, one carrying two wild alleles (wild group), and another carrying one or two mutant alleles (mutant group). Each group was further divided into two subgroups according to age; one subgroup consisted of 40s or 50s, and another consisted of 60s or 70s. The prevalence of the G994T mutation in the subjects was 28.6% (24.3% heterozygote, and 4.3% homozygote). IMT of the elderly patients of the mutant group was significantly greater (0.98 +/- 0.22 mm, n = 26) than of the elderly patients of the wild group (0.87 +/- 0.20 mm, n = 50, P = 0.0292). There was no significant difference in clinical characteristics between the two subgroups. The results of this study indicate that the missense mutation in plasma PAF acetylhydrolase is associated with development of atherosclerosis in the elderly.

Cellular and genetic analyses of IL-2 production and IL-2 receptor expression in a patient with familial T-cell-dominant immunodeficiency

Cellular and genetic analyses of interleukin-2 (IL-2) production and IL-2 receptor (IL-2R) expression were examined in a immunodeficient patient and his family members. Mononuclear cells (MNC) of the patient showed no proliferative response (stimulation index, less than 2) to T-cell mitogens (PHA and Con A) and were defective in IL-2 production and IL-2R expression (less than 1%), whereas productions of other lymphokines (B-cell differentiation factor and IFN-gamma) were not impaired significantly. His brother died of the same disease and his father also lacked in proliferative response and IL-2 production by PHA stimulation. In Southern blot analyses using DNA probes of IL-2 and IL-2R, patterns of the patient were the same as those of healthy volunteers, whereas the transcription of DNA coding for IL-2R to mRNA was lacking in the patient. These results suggest that inheritant defects of IL-2 production and IL-2R expression reside in this family and the defects are not linked to DNAs coding for IL-2 and IL-2R but to a transcriptional deficiency.

Peripheral blood T lymphocytes and basophils, freshly isolated from house-dust-mite-sensitive patients, produce interleukin-4 in response to allergen-specific stimulation.

We examined the capacity of interleukin-4 (IL) production from lymphocytes and basophils, isolated from the peripheral blood of allergic patients sensitive to house dust mite, after stimulation with mite extract. IL-4 production was measured by a sensitive bioassay based on coculture with CT.h4S (a human IL-4-responsive cell line). Lymphocytes and basophils from patients with elevated serum IgE specific to mite allergen [radioallergosorbent test (RAST) score > 3] could produce detectable levels of IL-4 in response to mite extract, whereas those from patients with a RAST score of less than 2 or normal volunteers could not. The sensitivity of basophils to mite extract was high, so that a lower concentration of mite extract (1-10 ng/ml) could induce maximal IL-4 production. On the other hand, a higher concentration (10 micrograms/ml) was required for maximal IL-4 production from the lymphocytes. These findings demonstrate that allergen-specific IL-4-producing cells, lymphocytes and basophils, are generated in vivo in allergic patients and also that there exist characteristic differences between lymphocytes and basophils related to the in vivo source of IL-4.

Nasal mucociliary clearance in patients with upper and lower respiratory diseases.

The nasal mucociliary clearance was measured in 71 subjects with nasal allergy (NA) (56 subjects without sinusitis and 15 with sinusitis), 12 subjects with bronchial asthma (BA) (7 without, 5 with) and 7 subjects with aspirin-induced asthma (AIA) using a saccharin test. The results were compared with those obtained in a control group of 15 healthy subjects. The saccharin time (ST) values for both NA and BA subjects without sinusitis (16.9 +/- 9.9 and 20.1 +/- 9.4 min, respectively) did not differ from that of the healthy subjects (16.3 +/- 5.3 min). However, ST values in NA and BA subjects with sinusitis (37.6 +/- 22.9 and 57.0 +/- 6.7 min, respectively) were significantly higher than those of healthy subjects (p < 0.01). The ST value of AIA subjects (13.0 +/- 5.4 min) showed no significant difference compared with that of the control group. These results suggest that allergic reactions do not influence the nasal mucociliary clearance and that the property of mucus complicated with sinusitis is important. Also, sinusitis observed in AIA may be somewhat different from ordinary sinusitis complicated with NA and BA.

A case report of a patient with rheumatoid arthritis complicated withMycobacterium aviumduring tocilizumab treatment

Abstract A female patient with rheumatoid arthritis (RA) suffered from Mycobacterium avium (M. avium) infection during tocilizumab treatment. Tocilizumab was discontinued and she was treated with a recommended chemotherapy, resulting in improvement of M. avium. Tocilizumab retreatment did not aggravate M. avium infection, and radiographic abnormalities improved over 1 year after cessation of the recommended therapy. Tocilizumab may be one candidate for intractable RA patients with M. avium if any biologic is required.