Given an abstract, indicate which of the provided candidate titles (Option1 and Option2) best describes it (respond with the text of the title, not option1/2).

Example Input: Abstract: Human IgG4 antibodies directed against phospholipase A, the P1 antigen from Dermatophagoides pteronyssinus extracts, and cat albumin were found unable to cross-link antigen. Previously, it was demonstrated that IgG4 antibodies, in contrast to IgG1 antibodies, did not cross-link Sepharose-bound antigen and antigen added in solution. To eliminate the possibility that this phenomenon was caused by preferential binding of both IgG4 Fab fragments to the solid-phase-bound antigen, cross-linking of antigen was studied in a fluid-phase system. In this test, incapability of IgG4 antibodies to bridge two antigens was also found. As a result of such a phenomenon, it is expected that immune complexes formed by IgG4 antibodies will be considerably smaller than complexes formed by IgG1. This was confirmed by analysis of the molecular size profiles of IgG1- and IgG4-containing immune complexes in sucrose-density gradients. Moreover, IgG1 was able to precipitate antigen in a radioimmunoprecipitation test, whereas precipitation was not demonstrable by the same amount of IgG4 antibodies. Even 3% polyethylene glycol 8,000 did not precipitate the small IgG4-containing immune complexes efficiently. The antibodies studied were of a high-affinity type, and there was no significant difference in association constants between IgG1 and IgG4 antibodies. Therefore, we were not able to confirm observations reported in the literature that the IgG4 subclass is associated with a low-affinity antibody response; probably, the affinity of the IgG4 antibodies was underestimated by other investigators because of the polyethylene glycol precipitation technique used to separate antibody-bound and free antigen. Our findings stress the point that IgG4 antibodies take a special place in the immune response upon chronic exposure to antigen.
Which is the apt title for the abstract? option1: Serologic aspects of IgG4 antibodies. II. IgG4 antibodies form small, nonprecipitating immune complexes due to functional monovalency. option2: 'Capture' of stereopsis by illusory contours [letter]
Example Output: Serologic aspects of IgG4 antibodies. II. IgG4 antibodies form small, nonprecipitating immune complexes due to functional monovalency.

Example Input: Abstract: In order to test the widely held assumption that homeopathic medicines contain negligible quantities of their major ingredients, six such medicines labeled in Latin as containing arsenic were purchased over the counter and by mail order and their arsenic contents measured. Values determined were similar to those expected from label information in only two of six and were markedly at variance in the remaining four. Arsenic was present in notable quantities in two preparations. Most sales personnel interviewed could not identify arsenic as being an ingredient in these preparations and were therefore incapable of warning the general public of possible dangers from ingestion. No such warnings appeared on the labels.
Which is the apt title for the abstract? option1: Arsenic content of homeopathic medicines. option2: Sensitivity of the Denver Developmental Screening Test in speech and language screening.
Example Output: Arsenic content of homeopathic medicines.

Example Input: Abstract: The purpose of the study reported here was to provide descriptive information about dean's letters, which are comprehensive summary letters sent near the end of students' undergraduate medical training by medical school deans to be part of the students' residency applications. Deans of student affairs at 124 U.S. medical schools were surveyed regarding composition of these letters at their institution. They were asked to describe themselves and the letters they write. Responses were received from 87 percent of these schools and provided data on types of information included in the letters, the decision to edit evaluations, student participation in the letter-writing process, use of final summary statements, cost and length of letters, and attitudes toward the development of national letter-writing guidelines. Major findings of the survey show that 97 percent of the writers allocated more space for clinical evaluations than basic science evaluations. Less than 50 percent of the writers included the student's class rank. Almost all included narrative evaluations of the student's performance during the clinical years. Negative information on students was addressed inconsistently by the writers. Eighty-five percent of the writers categorized their students in final summary statements, but many of these failed to provide descriptions of the categories used or explanatory data. The present authors make recommendations for writing more credible and useful letters.
Which is the apt title for the abstract? option1: National survey of writers of dean's letters for residency applications. option2: Philosophy of care.
Example Output:
National survey of writers of dean's letters for residency applications.