Polyclonal antibodies and catalysis

Stephens, David B.; Wilmore, Britta H.; Iverson, Brent L.

doi:10.1016/0968-0896(94)85014-3

Cited by 12 publications

(8 citation statements)

References 17 publications

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“…These values are termed ' apparent ' to emphasize that they characterize the polyclonal samples as a whole. Use of the fractions determined in the inhibition studies to estimate the catalyst concentration permits the calculation of the apparent k cat values also listed in Table 2 [11,[13][14][15][16][17]. In addition, the values of apparent k cat \k uncat can be calculated ; these are also listed in Table 2.…”

Section: Figure 1 Representative Inhibition and Lineweaver-burk Plotsmentioning

confidence: 99%

“…The great majority of previous catalytic antibody studies have utilized monoclonal antibodies. In contrast, antibody catalysis has been reported in polyclonal antibody preparations isolated from the sera of immunized animals [8][9][10][11][12][13][14][15][16][17][18][19]. Compared with monoclonal antibody studies, the investigation of antibody catalysis with polyclonal antibodies is substantially faster and far less expensive.…”

Section: Introductionmentioning

confidence: 99%

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Polyclonal antibody catalytic variability

Stephens

Thomas

Stanton

et al. 1998

Biochemical Journal

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We have performed a systematic variability study of polyclonal antibody catalysis by using five rabbits immunized with the same hapten. Important results from this work are the following. (1) Similarities were observed in the catalytic polyclonal antibodies derived from all five rabbits. Four of the five rabbits produced polyclonal samples that were nearly the same in terms of catalytic activity, whereas the fifth rabbit, designated as rabbit 2, displayed a somewhat higher level of catalytic activity. The catalytic activities (as kcat/kuncat) of these polyclonal samples were similar to that from the best murine monoclonal antibody that had been previously elicited by the same hapten. (2) Titre was not an accurate indicator of polyclonal antibody catalytic activity. (3) A mathematical analysis to describe a distribution of Michaelis-Menten catalysts was performed to help interpret our results. (4) Kinetic analysis indicated that the binding parameters of the different samples were remarkably homogeneous, because one or two components were all that were required to fit the on-rate and off-rate data satisfactorily. Interestingly, the most active catalytic polyclonal sample, that from rabbit 2, displayed the slowest off-rate (so slow it could not be measured) and thus the highest overall affinity. (5) Catalytic analysis of eluted fractions of antibody from a substrate column indicated that each polyclonal sample was also relatively homogeneous in terms of catalytic parameters. The main conclusion of our study is that for this hapten-animal system, the overall catalytic immune response is relatively consistent at two levels. Consistent catalytic activity was observed between the polyclonal samples elicited in the different animals, and the elicited hapten-specific polyclonal antibodies were relatively homogeneous in terms of binding and catalytic parameters within each immunized animal. The observed similarities of the catalytic activity in the different animals is surprising, because the immune response is based on specific binding of antibodies to hapten. There is no known selective pressure to maintain consistent levels of catalytic activity. Our results can therefore be interpreted as providing evidence that for this hapten there is a fixed relationship between hapten structure and catalytic activity and/or consistent genetic factors that dominate the catalytic immune response.

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Section: Figure 1 Representative Inhibition and Lineweaver-burk Plotsmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

Polyclonal antibody catalytic variability

Stephens

Thomas

Stanton

et al. 1998

Biochemical Journal

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“…The finding (reviewed in [12]) that, despite early discouraging results [13,14], substantial catalytic activities can be generated reproducibly in polyclonal preparations [15][16][17][18][19][20] suggests valuable opportunities for studies and applications complementary to those involving monoclonal catalytic antibodies. The particular value of the former, pointed out in [16] and emphasized by others [12,20,21], includes : (i) the relative simplicity of producing polyclonal as against monoclonal antibodies, (ii) their potential value as catalysts for technological applications, (iii) the rapid and cost-effective application in evaluating a range of haptens for production of catalytic activity, and (iv) their potential value in the development of novel therapies when produced by active immunization [18,19]. Because polyclonal IgG necessarily represents the entirety of the immune response, the relative immunogenic capabilities of a series of haptens may be assessed more effectively than by studies on a small selection of isolated monoclonal antibodies [20].…”

Section: Introductionmentioning

confidence: 99%

Characterization of the hydrolytic activity of a polyclonal catalytic antibody preparation by pH-dependence and chemical modification studies: evidence for the involvement of Tyr and Arg side chains as hydrogen-bond donors

Resmini

Vigna

Simms

et al. 1997

Biochemical Journal

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The hydrolyses of 4-nitrophenyl 4h-(3-aza-2-oxoheptyl)phenyl carbonate and of a new, more soluble, substrate, 4-nitrophenyl 4h-(3-aza-7-hydroxy-2-oxoheptyl)phenyl carbonate, each catalysed by a polyclonal antibody preparation elicited in a sheep by use of an analogous phosphate immunogen, were shown to adhere closely to the Michaelis-Menten equation, in accordance with the growing awareness that polyclonal catalytic antibodies may be much less heterogeneous than had been supposed. The particular value of studies on polyclonal catalytic antibodies is discussed briefly. Both the k cat and k cat \K m values were shown to increase with increase in pH across a pK a of approx. 9. Groupselective chemical modification studies established that the side

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“…Reasons for the growing interest in polyclonal catalytic antibody (PCA) preparations (e.g. Gallacher et al, 1991Gallacher et al, , 1992Gallacher et al, , 1993Green & Glikson, 1991;Stephens et al, 1994;Suzuki, 1994;Resmini et al, 1997) include: the relative simplicity of producing PCAs, their potential value in technological applications, the rapid and cost-e!ective application in evaluating a range of haptens for catalyst production and their potential value in the development of novel therapies when produced by active immunization. Because polyclonal IgG necessarily represents the entirety of the immune response, the relative immunogenic capabilities of a series of haptens may be assessed more e!ectively by using PCAs than by studies on a small selection of isolated monoclonal catalytic antibodies.…”

Section: Introductionmentioning

confidence: 99%