Blocking Type I Interferon (IFN) Signaling Impairs Antigen Responsiveness of Circulating Lymphocytes and Alters Their Homing to Lymphoid Organs: Protective Role of Type I IFN

Abstract

Background: We recently demonstrated that type I Interferon (IFN) rescues in vitro, human B-lymphocytes from apoptosis via PI3Kδ/Akt, Rho-A, NFĸB and Bcl-2/BclXL. In the present study we extended our work to clarify, in vivo, the role of type I IFN signalling on the circulating and lymphoid organs homing lymphocytes. Methodology: Two groups of mice 13 in each were set: type I IFN signalling blocked mice injected with anti-IFNAR1 antagonist antibody (10 mg/kg body weight) once/day for up to 20 days, and control group were injected with vehicle alone. Results: Flow cytometry analysis to monitor the blood lymphocyte phenotype and proliferation have shown a significant decrease in CD45R/CD220⁺ B cells, CD4⁺ and CD8⁺ T cells in treated animals. Furthermore, the proliferative capacities of these lymphocyte subsets were significantly decreased in treated animals compared to those of control mice. Marked reduction in the plasma levels of IL-2 and IL-7 (cytokines important for the development of T and B cells) but not of IL-6 or IL-10 was observed in treated mice and this may a cause for emergence decrease in B and T cell numbers. Immunohistochemical studies have further shown a marked reduction in the numbers of CD20⁺ B cells in spleen and Peyer’s patches and CD3⁺ T cells in thymus of treated animals. Moreover, electron microscopy examinations have revealed a loss of lymphocytes with characteristic features of apoptosis. Conclusion: Our data confirmed that the in vivo inhibition of type I IFN signaling induce decrease in the numbers and defective functions of circulating and lymphoid organs homing lymphocytes providing a strong evidence for the protective effects of type 1 IFNs (IFN-α/ β) on B and T lymphocytes.

Increased Levels of Type 1 Interferon in a Type 1 Diabetic Mouse Model Induce the Elimination of B Cells from the Periphery by Apoptosis and Increase their Retention in the Spleen

“…Forty Swiss Webster mice were assigned to three experimental groups: group 1, the non-diabetic control group (n=10), was injected with vehicle alone (0.01 M citrate buffer, pH 4.5); group 2, the diabetic group (n=15), was rendered diabetic by intraperitoneal injection of a single dose of STZ (60 mg per kilogram of body weight) in 0.01 M citrate buffer (pH 4.5); group 3 (n=15) was rendered diabetic using the same procedure as in group 2 but was also injected intraperitoneally, one month after diabetes induction, with an anti-IFN (alpha, beta and omega) receptor 1 (IFNAR1) antibody at a dose of 10 mg per kilogram of body weight daily for up to 20 days [36,37]. …”

Elevated IFN-alpha/beta levels in a streptozotocin-induced type I diabetic mouse model promote oxidative stress and mediate depletion of spleen-homing CD8+ T cells by apoptosis through impaired CCL21/CCR7 axis and IL-7/CD127 signaling

“…A C C E P T E D M A N U S C R I P T ACCEPTED MANUSCRIPT 6 ; group 3 (n=15) was rendered diabetic using the same procedure as in group 2 but was also injected intraperitoneally, 1 month after diabetes induction, with an anti-IFNAR1 antibody at a dose of 10 mg per kilogram of body weight daily for up to 20 days, as previously described [39].…”

Blocking Type I Interferon Signaling Rescues Lymphocytes from Oxidative Stress, Exhaustion, and Apoptosis in a Streptozotocin-Induced Mouse Model of Type I Diabetes

“…These animals were maintained under standard laboratory conditions (25°C temperature, 60–70% relative humidity, and 12 hour light/dark cycle) and were fed a standard commercial pellet diet and water. Forty Swiss Webster mice were divided into three experimental groups: group 1, the nondiabetic control group ( n = 10), was injected with the vehicle alone (0.01 M citrate buffer, pH 4.5); group 2, the diabetic group ( n = 15), was rendered diabetic with an intraperitoneal injection of a single dose of STZ (60 mg/kg body weight) in 0.01 M citrate buffer (pH 4.5) [12, 13]; group 3 ( n = 15) was rendered diabetic with the same injection but was also administered intraperitoneal injections with an anti-IFNAR1 antibody at a dose of 10 mg per kilogram of body weight daily for up to 20 days [27]. …”

“…Lysates were then prepared as previously described [27], and equal amounts of the total cellular protein were subjected to SDS-PAGE and blotted onto a nitrocellulose membrane (Millipore, Bedford, MA, USA). After primary antibodies recognizing phospho-STAT1, STAT1, phospho-STAT2, STAT2, phospho-I κ B, I κ B, AKT, and phospho-AKT (Cell Signaling, UK) were diluted at 1 : 1000 in 1X TBS with 0.1% Tween-20 and 5% bovine serum albumin (BSA), the membrane was incubated overnight with a primary antibody on an orbital shaker at 4°C.…”