Francine Cigel

Human T cells in hu‐PBL‐SCID mice proliferate in response to Daudi lymphoma and confer anti‐tumour immunity

In vitro culture of human peripheral blood lymphocytes (PBL) with Daudi (Burkitt lymphoma) cells results in selective proliferation of Vγ9/Vδ2 T cells with high cytotoxicity against Daudi cells. After adoptive transfer into severe combined immunodeficient (SCID) mice, these cells exert specific anti‐tumour activity against Daudi lymphoma. To test whether cytotoxic Vγ9/Vδ2 T cells are induced in SCID mice, human PBL injected intraperitoneally were stimulated with irradiated Daudi cells (PBL/ Daudi‐SCID). After 7–14 days, PBL/Daudi‐SCID had a significantly higher percentage of human γδ T cells in their peritoneal cavity, lymph nodes and blood than controls (PBL‐SCID). DNA content analysis of T cell subsets from PBL/Daudi‐SCID showed a significantly higher percentage of cells in S + G2+M phases of the cell cycle in the TCR‐γδ‐1+ than in CD3+ cell population. Human cells recovered from PBL/Daudi‐SCID showed specific cytotoxicity against Daudi cells. PBL/Daudi‐SCID inoculated with a lethal dose of Daudi lymphoma survived significantly longer than controls. This protection was specific for Daudi cells and was not mediated by murine natural killer (NK) cells. Thus human peripheral blood T cells grafted in SCID mice proliferate in response to antigen and confer specific immunity.

In vitro preacdvated human T cells engraft in SCID mice and migrate to murine lymphoid tissues

Mice with severe combined immunodeficiency (SCID) accept grafts of human T and B lymphocytes derived from resting peripheral blood mononuclear cells (PBMC). We wished to determine whether activated human T cells engraft and migrate into lymphoid tissues in SCID mice. PBMC (50 × 106) activated in vitro in a 4‐day mixed lymphocyte culture (MLC) were injected into the peritoneum of 12 SCID mice. In 11 of 12 animals killed at 3 or 4 weeks after injection, human cells were detected in cells pooled from lymphoid organs by flow cylomctry and by immunohistochemical staining of frozen tissue sections. The percentage of CD45+ cells in the 11 mice ranged from 2% to 45% and the absolute numbers of CD45+ cells recovered from lymphoid organs ranged from 4 × 106 to 90 × 106. Up to 93% of the human cells expressed the CD3 antigen together with either CD4 or CDS. Human T cells were localized in periarteriolar areas in murine spleens, whereas in the lymph nodes and gut mucosa, the T cells did not show the pattern for T‐dependcnt areas found in human lymphoid tissue. Numerous human plasma cells were detected in the spleen and gut mucosal crypts of engrafted SCID mice. Human IgG was delected in the serum of all 11 engrafted SCID mice. The functional activity of human T cells recovered from murine splenic tissue was very low 3–4 weeks after engraftment.

Immunity to blood-stage murine malarial parasites is MHC class II dependent

To determine whether MHC class II antigen presentation is essential for the induction of protective immunity against blood-stage malarial parasites, we used gene-targeted knockout (KO) mice to follow the time-course of nonlethal Plasmodium yoelii and Plasmodium chabaudi infections in two models of MHC class II deficiency. Infection of MHC class II KO (A(-/-)) mice with either parasite species resulted in an unremitting hyperparasitemia, whereas MHC-intact control mice resolved their parasitemia. In contrast, invariant chain KO (Ii(-/-)) mice, which present antigen via recycled but not nascent MHC class II molecules, eventually cured their infections when infected with P. yoelii. P. chabaudi parasitemia declined to subpatent levels in most Ii(-/-) mice but then recrudesced. Immunity to blood-stage malaria may be achieved by cell-mediated and antibody-mediated mechanisms of immunity, as such, the findings in A(-/-) mice indicate an essential role for MHC class II presentation of malarial antigens. Moreover, they suggest that protective immune responses to malarial antigens capable of eliminating blood-stage parasites are T cell dependent and can be induced with antigens processed in early and late endosomes.

Prolonged intermittent virus shedding during an outbreak of canine influenza A H3N2 virus infection in dogs in three Chicago area shelters: 16 cases (March to May 2015)

OBJECTIVE To estimate an appropriate isolation period for dogs infected with canine influenza A H3N2 virus on the basis of the duration of virus shedding. DESIGN Retrospective case series. ANIMALS 16 dogs, from 3 Chicago area shelters, naturally infected with canine influenza A H3N2 virus. PROCEDURES Medical records of 16 affected dogs were reviewed. Nasal swab specimens from each dog had been tested periodically for a minimum of 15 days following an initial positive real-time reverse transcriptase PCR (rRT-PCR) assay result for influenza A virus shedding. Amplicons were purified, quantified, and sequenced by the Sanger DNA sequencing technique. Virus isolation and sequence results of canine influenza A H3N2 virus from nasal swab specimens were obtained in conjunction with signalment, description of clinical signs, type of treatment, and outcome. RESULTS Viruses from each dog were identified as canine influenza A H3N2 virus on the basis of DNA sequencing. The interval between first and last positive rRT-PCR assay results ranged from 13 to 24 days, whereas the time interval from first reported clinical signs to last positive assay results ranged from 15 to 26 days. Isolation of canine influenza A H3N2 virus was successful in the late shedding period from nasal swab specimens of 4 dogs at 15 and 20 days after the first positive rRT-PCR assay result and 18 to 20 days after the first clinical signs. Clinical signs resolved for all dogs that remained in the shelters during the testing period. CONCLUSIONS AND CLINICAL RELEVANCE Dogs infected with H3N2 virus should be isolated for a period of ≥ 21 days following onset of illness. Even when resolution of clinical signs occurs sooner than 21 days, shedding of H3N2 virus may persist.

First detection of avian lineage H7N2 in Felis catus

ABSTRACT In December 2016, influenza A (H7N2) was first detected among cats in the New York City shelter system with subsequent widespread transmission. The sequence of the first clinical isolate, A/feline/New York/16-040082-1/2016(H7N2), and its genetic similarity to the live bird market lineage of H7N2 low-pathogenicity avian influenza are described.

Beak necrosis in Hungarian partridges (Perdix perdix) associated with beak-bits and avian poxvirus infection

Proliferative growth, consistent with poxvirus infection, encapsulated plastic beak-bits and covered the dorsal portion of the upper beak and nares of adult male and female captive-raised Hungarian partridges. Three representative birds were submitted to the Wisconsin Veterinary Diagnostic Laboratory for necropsy. Lesions in the necropsied birds extended through the nares, where the plastic bit ends are designed to rest. The lesions also variably extended caudally into the oropharynx and cranially within the beak epithelium, and included palate deformity and beak necrosis. Poxvirus was diagnosed in all of the birds examined based on histopathology, electron microscopy, and polymerase chain reaction amplification and sequencing. This report is the first to describe avian pox lesions associated with the application of beak-bits and the resulting beak and oral pathology.

Survival and tissue distribution of human T-cell clones in SCID mice

Evidence from animal experiments and clinical trials suggests that in vitro expanded T-cell clones could be useful in adoptive therapy of cancer and viral infections. To establish an in vivo model for adoptive therapy with cloned human T cells, we studied the survival and tissue distribution of human αβ CD4 + T-cell clones transplanted intraperitoneally into mice with severe combined immune deficiency (SCID) mice. Four clones, expanded in vitro in recombinant human interleukin-2 (IL-2), were injected into 14 cyclophosphamide-conditioned mice, subsequently inoculated daily with IL-2. Using flow-cytometry analysis, human T cells were detected in the peritoneal cavity wash (PCW) but not in other tissues of 12 mice at 1 to 4 weeks after injection. A reverse transcriptase polymerase chain reaction (RT-PCR) specific for the constant region of human TCR β chain revealed a positive signal in 12 of 14 mice in PCW, eight in spleen, seven in lymph nodes, seven in liver, six in bone marrow, and two in blood. The frequency of human T-cell detection decreased with time. Five to seven sites were positive in mice killed at 1 week, one to four sites at 2 weeks, none to one site at 3 weeks, and three sites at four weeks. Thus human T-cell clones transplanted in SCID mice can survive for at least 4 weeks, even in the absence of specific antigen. The clones migrate at low levels outside the peritoneal cavity ; therefore, the SCID mouse might serve as a model to study adoptive therapy with cloned T cells.