Evaluation of thymic lymphocyte loss of broiler using Digital Analysis of the Lymphoid Depletion System (ADDL)

The thymus is a lymphoid organ and usually evaluated for the degree of lymphocyte loss with subjective histological techniques. This study aimed to adapt and to apply of the digital analysis of the lymphoid depletion system (ADDL) in the thymus in order to obtain a more accurate analysis. Glucocorticoid was used to induce immunosuppression in 55 broilers at 21 days of age; other 15 broilers were the control group. After euthanasia of the broilers, postmortem examination was made. Both thymic chains were collected and six lobes were selected for histological examination of the degree of lymphocyte depletion (scores 1 to 5) and for submission to all stages of processing by the ADDL system. The artificial constructed neural networks (ANN) obtained 94.03% of correct classifications. In conclusion, it was possible to adopt objective criteria to evaluate thymic lymphoid depletion with the ADDL system.

T Lymphocyte Maturation Is Impaired in Healthy Young Individuals Carrying Trisomy 21 (Down Syndrome)

Cytokine production, immune activation, T lymphocytes maturation, and serum IL-7 concentration were examined in 24 youngsters with Down syndrome and no acquired diseases (healthy Down syndrome [12 prepubertal, 13 pubertal]) and 42 age- and gender-matched controls (20 prepubertal, 22 pubertal). Results showed that a complex immune and impairment is present in healthy individuals with Down syndrome in whom interferon gamma, interleukin (IL) IL-10 production, as well as serum IL-7 concentrations and activation markers-bearing T lymphocytes were significantly augmented. Additionally, a complex skewing of post-thymic lymphocyte maturation pathways was observed in patients: significant reduction of CD4+ and CD8+ naive (RA+CCR7+) lymphocytes, significant increase of CD4+ and CD8+ central memory (RA-CCR7+), and terminally differentiated (TD) (RA+CCR7−) lymphocytes.

Induction of Endoplasmic Reticulum Stress in Thymic Lymphocytes by the Envelope Precursor Polyprotein of a Murine Leukemia Virus during the Preleukemic Period

ABSTRACT Infection of thymic lymphocytes by a mink cell focus-forming murine leukemia virus induces apoptosis during the preleukemic period of lymphomagenesis. In this study, we observed that during this period, the viral envelope precursor polyprotein accumulated to high levels in thymic lymphocytes from mice inoculated with virus. Envelope accumulation occurred with the same kinetics as the induction of endoplasmic reticulum (ER) stress, which resulted in the upregulation of the 78-kDa glucose-regulated protein (GRP78). In thymic lymphomas, GRP78 levels were higher than those in virus-infected preleukemic cells, and GRP58 was upregulated. These results suggest that Env precursor accumulation induces ER stress, which participates in thymic lymphocyte apoptosis. The subsequent upregulation of ER chaperone proteins GRP78 and GRP58 may contribute to rescuing cells from virus-induced apoptosis.

Characterization of Upper Respiratory Disease in Rats Following Neonatal Inoculation with a Rat-adapted Influenza Virus

Neonatal F344 rats were infected with a rat-adapted influenza virus (RAIV) to use as a potential model to study the combined effects of air pollutant exposure with early life respiratory viral infections. Initially, 6-day-old pups were intranasally inoculated with RAIV or medium alone, and nasal and lower respiratory tract (LRT) tissues were assessed histologically at 1, 3, 6, and 13 days postinoculation (DPI). Immunologic assessments included thymic lymphocyte quantification and anti-RAIV immunoglobulin production. Pups then received two inoculations (at 6 and 30 days of age), with histologic and immunologic assessment 6 and 13 days after the second inoculation and bronchoprovocation testing 5-8 weeks later. Following the single RAIV inoculation, IgM and IgG1 measurements increased at 6, 11, and 15 DPI, with IgG1 being greater at 11 and 15 DPI. Nasal lesions were evident as early as 1 DPI and primarily involved the anterior dorsal medial meatus and adjacent dorsal atrio- and nasoturbinates. Alterations included epithelial cell exfoliation and necrosis, mild erosions, suppurative and nonsuppurative inflammation, intraepithelial neutrophil accumulations, and intraluminal exudate. By 3 DPI, olfactory epithelial damage was multifocal or locally diffuse, with degeneration of sensory cells and variable inflammation. By 13 DPI, lesions were essentially repaired. Minimal changes were apparent in the LRT despite evidence of viral replication in the lungs 24 hours after inoculation (>3 log10 plaque-forming units/lung). Pups reinoculated with RAIV at 30 days of age did not develop significant histologic lesions, nor did they exhibit increased airway responsiveness when assessed as young adults. In spite of their immature immune status at the time of initial infection, 13 days after the second RAIV inoculation, IgG, increased substantially. Thus, neonatal RAIV infection resulted in acute nasal epithelial injury and inflammation, alterations that may allow subsequent evaluation of viral disease-air pollutant interactions.