Maternal transmission of SIVsmm in rhesus macaques

Fifteen SIV-infected rhesus monkeys delivered 13 livebirths and two stillbirths; one livebirth died at three days of age. While all infants were culture-negative for SIV at birth, nine had maternal antibodies that disappeared by six months of age. Three infants subsequently seroconverted and became virus positive at 9–15 months. Milk samples from all mothers were virus-negative at parturition but samples from four animals were virus-positive at nine and 12 months. This study documents maternal transmission of SIV and suggests transmission by breast-feeding.     

Characterization of a keratinocyte-derived T cell growth factor distinct from interleukin 2 and B cell stimulatory factor 1

Epidermal epithelial cells (keratinocytes) produce and secrete a variety of immunologically active cytokines. We have previously reported that both transformed (PAM 212) and normal murine keratinocytes produce a soluble factor which induces proliferation of the T cell line, HT-2. In the present study we sought to compare keratinocyte-derived T cell growth factor (KTGF) with other T cell growth factors, characterize its physicochemical properties, and substantially purify KTGF from PAM 212 conditioned medium. KTGF from PAM 212 conditioned medium was not inhibited by antibodies which block the effect of interleukin 2 (IL 2) (S4B6) or B cell stimulatory factor 1 (BSF 1) (11B11). KTGF is heat-stable, has an isoelectric point of 4.8, and a relative molecular mass of 16 to 23 kilodaltons under nonreducing conditions. KTGF activity was enhanced at least 41,413-fold by sequential hydroxylapatite bulk preparation, desalting by reversed-phase chromatography, gel filtration high pressure liquid chromatography (HPLC), and reversed-phase HPLC. Keratinocytes produce a T cell growth factor with physicochemical properties distinct from IL 2 and BSF 1. KTGF may play a role in regulating the growth and differentiation of T cells in the epidermis.     

Down-regulation of macaque ΓΔ+ T cells in lymphoid compartments after rectal infection with SIVsmmPBj14

The dynamics of T cells expressing the ΓΔ T-cell receptor in mucosae and other compartments during the course of human immunodeficiency virus (HIV)-1 infection are poorly understood. To examine the impact of an acquired immunodeficiency syndrome virus on the ΓΔ+ T-cell population, rectal inoculation of macaques with simian immunodeficiency virus (SIV)-PBj14 was used as a model. After rectal inoculation, five macaques were sacrificed on days 4, 5, or 7 and then assessed for changes in the ΓΔ T-cell receptor repertoire in different lymphoid compartments. There was decreased representation of ΓΔ+ T cells in the intestinal mucosae, blood, and spleens. Overall, the reduced number of total ΓΔ+ T cells was consistent with decreases in the VΓ or VΔ T-cell sub-populations. Nevertheless, there was no consistent deletion or expansion of a selected VΓ+ or VΔ+ cell sub-population. These results demonstrate that SIV-PBj14 replication and dissemination after mucosal inoculation resulted in a decline of detectable ΓΔ+ T cells, suggesting that macaque ΓΔ+ T cells are susceptible to down-regulation or destruction during acute SIV-PBj14 infection.     

HIV-infected humans, but not chimpanzees, have circulating cytotoxic T lymphocytes that lyse uninfected CD4+ cells

It has been suggested that autoimmune phenomena contribute to the depletion of CD4+ T cells and the development of AIDS in HIV-1 infected humans based, in part, on observations that some HIV-1-infected humans have autoantibodies reactive with Ag expressed on uninfected CD4+ cells. In this study, 11 of 14 asymptomatic HIV-1-infected homosexuals and hemophiliacs, but none of 17 uninfected homosexuals or heterosexuals, were found to have cytotoxic lymphocytes in blood that can lyse uninfected CD4+ T cells from humans and chimpanzees but not human B lymphoblastoid cells or mouse T cells. The cytotoxic PBL were concluded to be CTL rather than NK cells, with the phenotype being CD3+, TCR-1 alpha beta+, CD8+, CD4-, CD16- based on findings that PBL-mediated lysis of uninfected CD4+ cells was 1) blocked by a mAb to CD3, which inhibits CTL but not NK activity; 2) diminished by treatment of PBL with a mAb to CD8 and C, but not by treatment with mAb to CD4 or CD16 and C; and 3) blocked by mAb WT31 directed against the TCR-1 alpha beta. In contrast, PBL from HIV-1-infected chimpanzees, which to date have not developed AIDS, lacked detectable CTL lytic for uninfected CD4+ cells.     

Superinfection of a chimpanzee with a second strain of human immunodeficiency virus.

Two chimpanzees, one (C-499) infected with the acquired immunodeficiency syndrome-associated retrovirus type 2 (ARV-2) strain of human immunodeficiency virus (HIV) and one (C-560) infected with the lymphadenopathy-associated virus type 1 (LAV-1) strain of HIV, were inoculated with approximately 10(4) tissue culture infective doses of the reciprocal strain. At the time of the second inoculation, both chimpanzees had high titers of HIV-specific antibodies, including antibodies that neutralized both virus strains. After inoculation of the second strain of HIV, the antibody titers in both chimpanzees increased 4- to 10-fold, and in one chimpanzee (C-499), the numbers of infectious peripheral blood mononuclear cells (PBMC) increased 1,000-fold to levels that are comparable with those observed after primary HIV infections. By restriction enzyme analysis of virus recovered from PBMC, both ARV-2 and LAV-1 were identified in C-499, thus demonstrating that superinfection had occurred.     

HABP2 G534E Variant in Papillary Thyroid Carcinoma

The main nonmedullary form of thyroid cancer is papillary thyroid carcinoma (PTC) that accounts for 80–90% of all thyroid malignancies. Only 3–10% of PTC patients have a positive family history of PTC yet the familiality is one of the highest of all cancers as measured by case control studies. A handful of genes have been implicated accounting for a small fraction of this genetic predisposition. It was therefore of considerable interest that a mutation in the HABP2 gene was recently implicated in familial PTC. The present work was undertaken to examine the extent of HABP2 variant involvement in PTC. The HABP2 G534E variant (rs7080536) was genotyped in blood DNA from 179 PTC families (one affected individual per family), 1160 sporadic PTC cases and 1395 controls. RNA expression of HABP2 was tested by qPCR in RNA extracted from tumor and normal thyroid tissue from individuals that are homozygous wild-type or heterozygous for the variant. The variant was found to be present in 6.1% familial cases, 8.0% sporadic cases (2 individuals were homozygous for the variant) and 8.7% controls. The variant did not segregate with PTC in one large and 6 smaller families in which it occurred. In keeping with data from the literature and databases the expression of HABP2 was highest in the liver, much lower in 3 other tested tissues (breast, kidney, brain) but not found in thyroid. Given these results showing lack of any involvement we suggest that the putative role of variant HABP2 in PTC should be carefully scrutinized.     

Protection against lethal simian immunodeficiency virus SIVsmmPBj14 disease by a recombinant Semliki Forest virus gp160 vaccine and by a gp120 subunit vaccine.

Infection of pigtail macaques with SIVsmmPBj14, biological clone 3 (SIV-PBj14-bc13), produces an acute and usually fatal shock-like syndrome 7 to 14 days after infection. We used this simian immunodeficiency virus (SIV) model as a rapid and rigorous challenge to evaluate the efficacy of two SIV Env vaccine strategies. Groups of four pigtail macaques were immunized four times over a 25-week span with either a recombinant Semliki Forest virus expressing the SIV-PBj14 Env gp160 (SFV-SIVgp160) or purified recombinant SIV-PBj14 gp120 (rgp120) in SBN-1 adjuvant. Antibody titers to SIV Env developed in all immunized animals (mean peak titers prior to challenge, 1:1,700 for SFV-SIV gp 160 and 1:10,500 for rgp120), but neither neutralizing antibodies nor SIV-specific T-cell proliferative responses were detectable in any of the vaccinees. All macaques were challenged with a 100% infectious, 75% fatal dose of SIV-PBj14-bc13 at week 26. Three of four control animals died of acute SIV-PBj14 syndrome on days 12 and 13. By contrast, all four SFV-SIVgp160-immunized animals and three of the four rgp120-immunized animals were protected from lethal disease. While all virus-challenged animals became infected, symptoms of the SIV-PBj14 syndrome were more severe in controls than in vaccinees. Mean virus titers in plasma at 13 days postchallenge were approximately 10-fold lower in vaccinated than control animals. However, there was no apparent correlation between survival and levels of peripheral blood mononuclear cell-associated culturable virus, provirus load, or any antiviral immunologic parameter examined. The results indicate that while immunization with SFV-SIVgp160 and rgp120 did not protect against virus infection, these Env vaccines did lower the virus load in plasma and protect against the lethal SIV-PBj14 challenge.     

Virus-specific cytotoxic T lymphocytes in human immunodeficiency virus type 1-infected chimpanzees.

Chimpanzees have been important in studies of human immunodeficiency virus type 1 (HIV-1) pathogenesis and in evaluation of HIV-1 candidate vaccines. However, little information is available about HIV-1-specific cytotoxic T lymphocytes (CTL) in these animals. In the present study, in vitro stimulation of peripheral blood mononuclear cells (PBMC) from infected chimpanzees with HIV-1 Gag peptides was shown to be a sensitive, reproducible method of expanding HIV-1-specific CD8(+) effector CTL. Of interest, PBMC from two chimpanzees had CTL activity against Gag epitopes also recognized by major histocompatibility complex class I-restricted CTL from HIV-1-infected humans. The use of peptide stimulation will help to clarify the role of CTL in vaccine-mediated protection and HIV-1 disease progression in this important animal model.     

Combination of dasatinib and curcumin eliminates chemo-resistant colon cancer cells

Metastatic colorectal cancer remains a serious health concern with poor patient survival. Although 5-Fluorouracil (5-FU) or 5-FU plus oxaliplatin (FOLFOX) is the standard therapy for colorectal cancer, it has met with limited success. Recurrence of the tumor after chemotherapy could partly be explained by the enrichment of the chemo-resistant sub-population of cancer stem cells (CSCs) that possess the ability for self-renewal and differentiation into different lineages in the tumor. Therefore development of therapeutic strategies that target CSCs for successful treatment of this malignancy is warranted. The current investigation was undertaken to examine the effectiveness of the combination therapy of dasatinib (a Src inhibitor) and curcumin (a dietary agent with pleiotropic effect) in inhibiting the growth and other properties of carcinogenesis of chemo-resistant colon cancer cells that are enriched in CSCs sub-population. Remnants of spontaneous adenomas from APC ^{Min +/-} mice treated with dasatinib and/or curcumin were analyzed for several cancer stem cell markers (ALDH, CD44, CD133 and CD166). Human colon cancer cells HCT-116 (p53 wild type; K-ras mutant) and HT-29 (p53 mutant; K-ras wild type) were used to generate FOLFOX resistant (referred to as CR) cells. The effectiveness of the combination therapy in inhibiting growth, invasive potential and stemness was examined in colon cancer CR cells. The residual tumors from APC ^{Min +/-} mice treated with dasatinib and/or curcumin showed 80-90% decrease in the expression of the CSC markers ALDH, CD44, CD133, CD166. The colon cancer CR cells showed a higher expression of CSCs markers, cell invasion potential and ability to form colonospheres, compared to the corresponding parental cells. The combination therapy of dasatinib and curcumin demonstrated synergistic interactions in CR HCT-116 and CR HT-29 cells, as determined by Calcusyn analysis. The combinatorial therapy inhibited cellular growth, invasion and colonosphere formation and also reduced CSC population as evidenced by the decreased expression of CSC specific markers: CD133, CD44, CD166 and ALDH. Our data suggest that the combination therapy of dasatinib and curcumin may be a therapeutic strategy for re-emergence of chemo-resistant colon cancer by targeting CSC sub-population.