Protective immunity of gene-deleted SHIVs having an HIV-1 Env against challenge infection with a gene-intact SHIV

We constructed three simian-human immunodeficiency viruses (SHIVs) lacking regulatory gene(s) and analyzed their induction of protective immunity against challenge infection with gene-intact SHIV in rhesus macaques. Inoculation of SHIV-dn lacking nef and SHIV-drn lacking nef and vpr induced transient viremia, while that of SHIV-dxrn lacking nef, vpr, and vpx induced no viremia. The SHIVs with fewer deletions were more effective in inducing neutralizing antibodies and cytotoxic T lymphocyte responses. When these macaques were challenged with parental gene-intact SHIV-NM-3rN, all the SHIV-dn-vaccinated macaques and two of the four SHIV-drn-vaccinated macaques showed complete resistance. The other two SHIV-drn-vaccinated macaques and all SHIV-dxrn-vaccinated macaques did not show complete resistance, but they did show suppression of replication of the challenge virus. These results suggested that as more genes were deleted, protective immunity was decreased.     

Crystallization and preliminary X-ray study of the cathepsin B complexed with CA074, a selective inhibitor.

Cathepsin B from bovine spleen has been purified and crystallized as a complex with a specific inhibitor CA074 [N-(L-3-trans-propylcarbamoyloxirane-2-carbonyl)-L- isoleucyl-L-proline], using the hanging-drop method. The complex crystals obtained from 50 mM-citrate buffer (pH 3.5) belong to the tetragonal space group P4(1) (or P4(3)) with a = 73.06 A and c = 141.59 A, and diffract beyond 2.2 A resolution. There are two complex molecules per asymmetric unit giving a packing density of 3.37 A3/Da and indicating a high solvent content of 63.5%.     

The rice retrotransposon Tos17 prefers low-copy-number sequences as integration targets

The rice retrotransposon Tos17 is highly activated by tissue culture. To evaluate the impact of transposition of Tos17 on the rice genome and examine its utility for insertional mutagenesis, more than 100 sequences flanking newly transposed Tos17 copies were characterised. The 5-bp target-site duplications flanking Tos17 did not show any consensus sequence, and preferred nucleotides, A/T and G/C, were only found at the second and third nucleotides from both ends of the target site duplications, respectively, indicating that Tos17 has relatively low target-site specificity at the nucleotide sequence level. Integration targets were widely distributed over the chromosomes; however, preferential integration into the sucrose synthase 2 gene and into Tos17 itself was demonstrated by PCR screening using pooled DNA prepared from the mutant population. Hybridisation studies indicated that Tos17 preferentially integrates into low-copy-number regions of the genome. In agreement with this result, about 30% of flanking sequences examined showed significant homology to known genes. Taken together, these results show that Tos17 can have a significant impact on the rice genome and can be used as a tool for efficient insertional mutagenesis.     

Anti-citrullinated collagen type I antibody is a target of autoimmunity in rheumatoid arthritis

Rheumatoid arthritis (RA) is one of the most common autoimmune diseases, but its autoimmune mechanisms are not clearly understood. Recently, anti-citrullinated peptide antibodies have been specifically observed in sera of RA patients. Furthermore, we identified RA-susceptible variant in a gene encoding citrullinating enzyme, peptidylarginine deiminase type 4 (PADI4). Therefore, we hypothesized that proteins which are modified in RA synovium by PADI4 act as autoantigens. Subsequently, we obtained human collagen type I (huCI) as one of the autoantigens using a RA synoviocyte cDNA library by immunoscreening. We also investigated that the levels of anti-citrullinated huCI were significantly higher in RA patient sera than in normal control sera with high specificity (99%) and positively correlated with the levels of anti-cyclic citrullinated peptide (anti-CCP) antibodies. We concluded that huCI is a novel substrate protein of PADIs and that citrullinated huCI is a candidate autoantigen of RA.     

Role of humic acid fraction with higher aromaticity in enhancing the activity of a biomimetic catalyst, tetra(p-sulfonatophenyl)porphineiron(III)

To elucidate the structural features of humic acids (HAs) that potentially contribute to enhancing the activity of a tetra(p-sulfonatophenyl)porphineiron(III) (Fe(III)-TPPS) catalyst, the effects of the chemical properties of molecular weight fractionated HAs on the catalytic activity of Fe(III)-TPPS were investigated. Three fractions were obtained as the following order of molecular size: F3 < F2 < F1. The deactivation of Fe(III)-TPPS, which can be attributed to the self-degradation of Fe(III)-TPPS, was retarded in the presence of HAs, and the pseudo-first-order rate constant in the presence of F3 was the smallest of the three fractions. In addition, the highest catalytic activity, determined as the percent degradation of an organic substrate, was observed in the presence of F3. The enhanced catalytic activity of Fe(III)-TPPS was due to the formation of supramolecular complexes with HAs, and the formation constant for F3 was the largest. Thus, the F3 fraction was the most effective fraction. Solid-state CPMS 13C NMR spectra indicated that the aromaticity of F3 was the highest of all of the fractions. Thus, it can be concluded that aromatic moieties in HAs play an important role in the formation of supramolecular complexes with Fe(III)-TPPS, leading to an enhancement in catalytic activity.     

Human plasma adenosine deaminase 2 is secreted by activated monocytes

Adenosine deaminase (ADA) plays an important role in the immune system, and its activity is composed of two kinetically distinct isozymes, ADA1 and ADA2. ADA2 is a major component of human plasma total ADA activity and ADA2 activity is significantly elevated in patients with various diseases such as HIV infection and chronic hepatitis. However, relatively little is known about ADA2 because of difficulties in purifying this enzyme. In this study we succeeded in purifying human plasma ADA2 and demonstrate the extracellular secretion of ADA2 from human peripheral blood monocytes stimulated with phorbol 12-myristate 13-acetate and calcium ionophore.     

Sensitivity of the fetal rat pituitary-adrenal system to corticotropin-releasing factor in organ culture.

Six groups of adrenal glands from 17-day fetal rats were explanted to organ culture for 2 days. In one group, adrenal gland was cultured alone, and in the remaining five groups adrenal gland was cultured with pituitaries from fetuses ranging in age from 14 to 18 days. In each of the groups, half of the cultures had corticotropin-releasing factor (CRF) added to the medium. A histometric parameter utilized the size of adrenocortical cells as an indicator of sensitivity of the pituitary-adrenal system. When 17-day adrenal gland was cultured alone, addition of CRF did not cause any enlargement of cortical cells. When the adrenal gland was cultured with two 14-day pituitaries, cortical cells were enlarged. Addition of CRF to this culture induced no further change. With two 15-day pituitaries in the presence of CRF, cortical cells were slightly larger than those in the absence of CRF. With 16- to 18-day pituitaries, a marked hypertrophy of cortical cells was induced, and the addition of CRF caused further acceleration in their enlargement. These results suggest that, in organ culture, 14-day pituitary can release some adrenocorticotropic hormone (ACTH) with or without additional CRF. Older pituitaries (16- to 18-day) can apparently release an amount of ACTH in the presence of CRF that is greater than their own spontaneous ACTH secretion.