Given an abstract, generate a keyword (a noun phrase) that best describes the focus or contribution of the paper. Such keywords can be directly from the given abstract or outside it.

Ex Input:
Abstract: To investigate whether IgG antinuclear antibodies have cross-reactive rheumatoid factor activity, monoclonal IgG antibodies to DNA and Sm from autoimmune MRL-lpr/lpr mice were assayed by ELISA for binding to IgG antigens. Of the nine anti-DNA and anti-Sm monoclonals tested, six showed significant binding to affinity-purified rabbit IgG (RIgG) and human IgG (HIgG). To confirm that cross-reactivities were due to a single antibody, immunoabsorption of a representative polyspecific monoclonal termed C11 (anti-DNA, anti-Sm) on either Sepharose-DNA or Sepharose-RIgG resulted in marked loss of activity to the three antigens DNA, Sm and RIgG compared with immunoabsorption on Sepharose-bovine serum albumin. The monomolecular nature of the cross-reacting antibody was also suggested by inhibition analysis of C11; DNA inhibited C11 binding to RIgG 64%, whereas Sm inhibited binding to RIgG 33%. Aggregated RIgG and HIgG, however, did not inhibit binding of C11 to DNA, Sm, or solid-phase RIgG, probably reflecting the low affinity of this antibody for fluid phase Ig. Together, these findings suggest that antinuclear autoantibodies of the IgG, as well as the IgM, class have polyspecific IgG binding activity and suggest that IgG antinuclear antibodies may emerge from rheumatoid factor responses.

Ex Output:
Animal

Ex Input:
Abstract: Although osteoarthritis (OA) generally is considered a disorder of mechanical origin, the common occurrence of chronic mononuclear cell infiltrates in the synovium in conjunction with immunofluorescent evidence for immune-reactant products in cartilage of surgical case specimens (knees, hips, and peripheral joints) has suggested the local involvement of immune processes in the arthritis. Further, the findings of polyarthropathy in the majority of these cases have indicated the propensity for a systemic disorder. Wide variations were noted in both synovial and cartilage immune changes, quite different to those found in rheumatoid arthritis, along with the frequent asymptomatology of the many joints involved. These features, with and without other causative factors, suggest that immune reactions of local and/or systemic origin occur at times in a population at risk for joint degradation.

Ex Output:
Cartilage, Articular

Ex Input:
Abstract: Since its first isolation, bovine beta-lactoglobulin (BLG) has been an enigma: although it is abundant in the whey fraction of milk, its function is still not clear. The results of the many physicochemical studies on the protein need a structural interpretation. We report here the structure of the orthorhombic crystal form of cow BLG at pH 7.6, at a resolution of 2.8 A. It has an unusual protein fold, composed of two slabs of antiparallel beta-sheet, which shows a remarkable similarity to plasma retinol-binding protein. A possible binding site for retinol in BLG has been identified by model-building. This suggests a role for BLG in vitamin A transport and we have discovered specific receptors for the BLG-retinol complex in the intestine of neonate calves.

Ex Output:
Animal