EFFECT OF ANTI-KERATIN ANTIBODY ON HAIR 215 Figure 4. Demonstration of activity of fragments of the antibody. Ouchterlony's gel diffusion was done in 1.2% agar with PBS. K: hair keratin, A: intact antibody to hair keratin, C: F(ab') 2 fragment of antibody, D: Fab fragment of antibody, N: non-specific antibody, B: PBS buffer. Note inhibition of precipitin line near well D. The effect of these fragments on inhibiting fracture generation in hair by brushing is shown in Figure 5. The F(ab') 2 fragment inhibited fracture generation in hair as well as did the intact antibody. However, the Fab fragment was not as effective. This indicates that bivalent binding activity of the antibody is essential to inhibit fracture generation in hair by brushing. DISCUSSION The anti-keratin antibody bound dose-dependently to hair sections (Figure 1). In our previous studies, we observed that the rabbit anti-keratin antibody bound to hair fiber with an antigen-antibody reaction (6) and that the bovine anti-keratin antibody bound to a hair section through immunocytochemical study (7). The binding of non-specific antibody to hair was determined in Figure 2. No difference was observed in the amount of non-specific antibody binding to hair regardless of the type of damage. Little non-specific antibody bound to hair sections, even though sections were incubated with a high concentration of non-specific antibody (Figure 1). Judging from these results, it could be suggested that apparent binding of non-specific antibody to hair fiber was in the basal absorbance or was due to insufficient washing of the hair. The binding of the anti-keratin antibody to the damaged hair was significantly increased compared with virgin hair. The amount of antibody bound to hair is in proportion to the extent of damage (Figure 2). We suggest that the anti-keratin antibody selectively binds to the damaged regions of hair. The elastic modulus for stretching of mongoloid hair was 4.3 x 109 N/M 2 at a stretching rate of 5 cm/min, 65% relative humidity, and 22øC (Table I). C. R. Robbins (2) reported that that of caucasoid hair was 3.89 x 109 N/M 2 at a stretching rate of 0.25 cm/min, 60% relative humidity, and room temperature. Our value is similar to Robbins' data, though the source of human hair and the stretching rate are different. The anti-keratin antibody increased the elastic modulus in the Hooken region and the tensile strength on stretching of hair fibers (Table I). Polypeptides such as collagen

216 JOURNAL OF THE SOCIETY OF COSMETIC CHEMISTS 6o = 40 20 0 200 400 Number of brushing (strokes) Figure 5. Effect of fragments of the antibody on inhibiting fracture generation in permed hair. The hair lock was treated with the intact antibody (¸), F(ab')2 fragment (/•), Fab fragment ( 0 ), and solution buffer as a control ([-]). hydrolysate (3), ginseng saponin (4), and carboxymethyl chitin (5) increased the tensile strength of hair fiber, and collagen hydrolysate and ginseng saponin increased the elongation of hair (4). On the other hand, the antibody did not increase the elongation of hair. It was only observed that the elastic modulus was influenced by relative hu- midity or moisture content (11,12) and temperature (13). Judging from these results, we surmise that the antibody is influenced by a different mechanism from former materials the increased elastic modulus results in improvement of the tensile strength of the damaged hair. The antibody inhibited fracture generation in permed hair through excessive brushing (Figures 3, 5). Excessive brushing causes stretching of hair and then generates fractures of hair. In order to maintain its healthy state, it is important to raise the hair's resistance against stretching. We expect that the strengthening of the elastic modulus of hair fiber by treatment with antibody will result in inhibiting fracture generation of the hair.