IL-2Ralpha-Directed monoclonal antibodies provide effective therapy in a murine model of adult T-cell leukemia by a mechanism other than blockade of IL-2/IL-2Ralpha interaction.

Adult T-cell leukemia (ATL) develops in a small proportion of human T-cell lymphotrophic virus-I infected individuals. The leukemia consists of an overabundance of activated T cells, which are characterized by the expression of CD25, or IL-2Ralpha, on their cell surface. Presently, there is not an accepted curative therapy for ATL. We developed an in vivo model of ATL in non-obese diabetic/severe combined immunodeficient (NOD/ SCID) mice by introducing cells from an ATL patient (MET-1) into the mice. The leukemic cells proliferated in these mice that lack functional T, B, and natural killer (NK) cells. The MET-1 leukemic cells could be monitored by measurements of both serum soluble Tac (IL-2Ralpha) and soluble human beta2-microglobulin (beta2mu) by ELISA. The disease progressed to death in the mice after approximately 4-6 weeks. The mice developed grossly enlarged spleens and a leukemia involving ATL cells that retained the phenotype and the T-cell receptor rearrangement and human T-cell lymphotrophic virus-I integration pattern of the patient's ATL leukemia cells. This model is of value for testing the efficacy of novel therapeutic agents for ATL. The administration of humanized anti-Tac (HAT), murine anti-Tac (MAT), and 7G7/B6, all of which target IL-2Ralpha, significantly delayed the progression of the leukemia and prolonged the survival of the tumor-bearing mice. In particular, HAT induced complete remissions in 4 of 19 mice and partial remissions in the remainder. It appears that the antibodies act by a mechanism that had not been anticipated. The prevailing view is that antibodies to the IL-2Ralpha receptor have their effective action by blocking the interaction of IL-2 with its growth factor receptor, thereby inducing cytokine deprivation apoptosis. However, although both HAT and MAT block the binding of IL-2 to IL-2Ralpha of the high affinity receptor, the 7G7/B6 monoclonal antibody binds to a different epitope on the IL-2Ralpha receptor, one that is not involved in IL-2 binding. This suggested that the antibodies provide an effective therapy by a mechanism other than induction of cytokine deprivation. In accord with this view, the MET-1 cells obtained from the spleens of leukemic mice did not produce IL-2, nor did they express IL-2 mRNA as assessed by reverse transcription-PCR. Another possible conventional mechanism of action involves complement-mediated killing. However, although MAT and 7G7/B6 fix rabbit complement, HAT does not do so. Furthermore, in the presence of NOD/SCID mouse serum, there was no complement-mediated lysis of MET-1 cells. In addition, the antibodies did not manifest antibody-dependent cellular cytotoxicity with NOD/SCID splenocytes that virtually lack NK cells as the effector cells as assessed in an in vitro chromium-release assay. However, in contrast to the efficacy of intact HAT, the F(ab')2 version of this antibody was not effective in prolonging the survival of mice injected with MET-1 ATL cells. In conclusion, in our murine model of ATL, monoclonal antibodies, HAT, MAT, and 7G7/B6, appear to delay progression of the leukemia by a mechanism of action that is different from the accepted mechanism of IL-2 deprivation leading to cell death. We consider two alternatives: the first, antibody-dependent cellular cytotoxicity mediated by FcRI- or FcRIII-expressing cells other than NK cells, such as monocytes or polymorphonuclear leukocytes. The second alternative we consider involves direct induction of apoptosis by the anti-IL-2R antibodies in vivo. It has been shown that the IL-2R is a critical element in the peripheral self-tolerance T-cell suicide mechanism involved in the phenomenon of activation-induced cell death.

Oral Health in Primary Care: A Framework for Action.

KNOWLEDGE TRANSFER STATEMENT:: This special communication presents the Oral Health Delivery Framework, a conceptual model for incorporating preventive oral health care in routine medical care and improving referrals from primary care to dentistry. The framework, along with supporting case examples and stakeholder actions, was published in Oral Health: An Essential Component of Primary Care in June 2015. To access the full white paper and supporting resources, visit www.QualisHealth.org/white-paper .

Preparation and in vivo evaluation of linkers for 211At labeling of humanized anti-Tac.

The syntheses, radiolabeling, antibody conjugation, and in vivo evaluation of new linkers for 211At labeling of humanized anti-Tac (Hu-anti-Tac), an antibody to the alpha-chain of the IL-2 receptor (IL-2Ralpha) shown to be a useful target for radioimmunotherapy are described. Synthesis of the organometallic linker precursors is accomplished by reaction of the corresponding bromo- or iodoaryl esters with bis(tributyltin) in the presence of a palladium catalyst. Subsequent conversion to the corresponding N-succinimidyl ester and labeling with 211At of two new linkers, N-succinimidyl 4-[211At]astato-3-methylbenzoate and N-succinimidyl N-(4-[211At]astatophenethyl)succinamate (SAPS), together with the previously reported N-succinimidyl 4-[211At]astatobenzoate and N-succinimidyl 3-[211At]astato-4-methylbenzoate, are each conjugated to Hu-anti-Tac. The plasma survival times of these conjugates are compared to those of directly iodinated (125I) Hu-anti-Tac. The N-succinimidyl N-(4-[211At]astatophenethyl)succinamate compound (SAPS) emerged from this assay as the most viable candidate for 211At-labeling of Hu-anti-Tac. SAPS, along with the directly analogous radio-iodinated reagent, N-succinimidyl N-(4-[125I]astatophenethyl)succinamate (SIPS), are evaluated in a biodistribution study along with directly iodinated (125I) Hu-anti-Tac. Blood clearance and biological accretion results indicate that SAPS is a viable candidate for further evaluation for radioimmunotherapy of cancer.

Evaluation of the hip.

This paper deals with clinical evaluation of the hip. Methods of testing for mobility in the hip joint are discussed. Analysis of gait and functional activities as related to muscle imbalance is presented. Gross techniques of manual muscle testing and basic principles of specific manual muscle testing are presented.

Functional visual problems: training home care aides to identify early signs.

Home care aids are a primary source of direct care to frail elders, for whom vision loss is a key factor in their declining health. Together, a vision rehabilitation service and a home care aid service agency developed a training program to increase aides' awareness and sensitivity to the issues of visual impairment and to develop a referral system for appropriate eye care and vision rehabilitative services for their clients.

2'3'-Dideoxyinosine inhibits the humoral immune response in female B6C3F1 mice by targeting the B lymphocyte.

2',3'-Dideoxyinosine (ddI) is a purine nucleoside analog currently being used for the treatment of HIV-positive individuals and patients with AIDS. Preliminary immunotoxicity studies have shown that a consequence of ddI treatment in female B6C3F1 mice is the inhibition of the humoral immune response. This effect was dose dependent in a range of 100 to 1000 mg/kg with a no observed adverse effect level of less than 100 mg/kg for a 28-day treatment period. These studies were undertaken to investigate the immune cell target of ddI and to determine the mechanism of this toxicity. B6C3F1 mice were treated with 1000 mg/kg/day by oral gavage for 28 days. The B lymphocyte was identified as the cellular target of ddI through separation-reconstitution experiments of the adherent and nonadherent cell populations and of the T and B lymphocyte populations. These studies revealed a deficit in the ability of the nonadherent cells from ddI-treated mice to mount a normal antibody response to sRBC. A further separation of the nonadherent cells into T and B cells revealed a decreased ability of ddI-treated B cells to develop specific humoral immunity. Additional studies were undertaken to determine the mechanism by which ddI is affecting the B cell. Surface marker analysis of splenocytes revealed no difference in the cell populations between vehicle- and ddI-treated mice. B cell proliferation was also unaffected as shown by incubation with either a polyclonal stimulator, lipopolysaccharide, or anti-IgM plus IL-4. These results indicate that the primary cellular target of ddI is the B lymphocyte.

Synthesis and properties of an aggregating heterocyclic helicene.

Heterohelicene 10 is synthesized in six steps from 3,3'-bithienyl. Because the number of steps is small, because the yield is 95% in the last (the reaction of a bis-enol ether with 1,4-benzoquinone-a six-step one pot procedure that constructs the helicene skeleton), and because chromatography is not required to purify any of the products in the synthesis, significant amounts are easily prepared. To convert 10 into enantiopure 3, a helicenebisquinone surrounded by four dodecyloxy groups, requires only a precedented three-step sequence. Enantiopure helicene 3, either without solvent or in dodecane (but not in chloroform) aggregates into columnar structures whose optical properties differ markedly from those of the monomer but resemble those shown previously only by aggregates of 1. Evidence of aggregation in the pure material includes optical microscopic observation of long fibrous structures and X-ray diffraction and combined transmission electron microscopic and electron diffraction analyses showing the molecules within the fibers to be organized in columnar arrays. The circular dichroism spectra, specific rotations, and fluorescent emission spectra of the aggregated structures are all distinctive, and, as reported elsewhere, the second harmonic response is very large. The linear polarizations of the monomers' and aggregates' fluorescent emissions differ greatly. The circular polarization of the aggregates' fluorescent emission, after excitation by unpolarized light, is large.

Immunotoxicity of 2',3'-dideoxyinosine in female B6C3F1 mice.

2',3'-dideoxyinosine (ddI) is one of several purine analogues used for the treatment of HIV and the acquired immunodeficiency syndrome (AIDS). These nucleoside analogues are promising in their inhibition of viral reverse transcriptase and termination of DNA synthesis. However, each of these drugs has toxicity associated with its use. A previous immunotoxicological evaluation of 2',3'-dideoxyadenosine (ddA), the parent compound of ddI, showed that ddA suppresses humoral immunity. These studies were undertaken to determine the potential for immunotoxicity due to treatment with ddI. This evaluation included an assessment of innate and acquired immunity after exposure to ddI (100, 250, 500, and 1000 mg/kg/day) for 14, 28 or 180 days. There were no overt signs of toxicity related to treatment with ddI except for a decrease in body weight in the group treated with the highest dose of ddI for 180 days. Overall, 6 months of treatment with ddI showed minimal effects on specific organs with the exception of the spleen and thymus. ddI selectively targets the immune system, with assays that challenge humoral immunity being more affected than those testing cell-mediated immunity. Innate immunity was unaffected by ddI treatment. Cell-mediated immunity, as measured by proliferative response to allogeneic cells (MLR) and the T cell mitogen (Concanavalin A), was moderately suppressed. There were no ddI associated effects on NK function or macrophage function as measured by the vascular clearance rate and phagocytic uptake of the tissue macrophages. The most sensitive indicator of ddI-induced immunotoxicity is suppression of the response to the T-dependent antigen, sheep red blood cells (sRBC). The No Observable Adverse Effect Level (NOAEL) for toxicity to the immune system following 14 days of exposure to ddI is 250 mg/kg. A suppression of the humoral immune response was seen at the lowest dose tested after treatment for 28 and 180 days. Thus, the NOAEL for both of these treatment periods is below 100 mg/kg/day.