Protein antigen combination for alzheimer's disease detection and use

Abstract

A protein antigen for Alzheimer's disease detection comprises at least any two of DOC2A, LGALS1, KDM4D, and ADARB1 proteins at the same time, can be used for early detection or diagnosis of Alzheimer's disease, and is suitable for risk assessment and prediction of before the onset of Alzheimer's disease; moreover, the protein antigen can distinguish Alzheimer's disease from other types of dementia, and can be further prepared into a related reagent or kit according to requirements.

Description

[0061] Results indicate that in an event of judgment based on the "single-index" method, sensitivity was higher compared to three commonly used existing methods. However, specificity was relatively lower compared to the detection based on individual protein antigens, suggesting that the detection accuracy could be further improved.

[0062] 2. Antigen compositions are used for detection based on a "double-index" method.

[0063] The "double-index" method refers to an approach where when a certain sample to be tested is detected using a certain antigen combination, the detection result of the sample is regarded as positive if two or more antigens from the antigen combination yield positive detection signals; and otherwise, the result is regarded as negative. The rest of operations are the same as the "single-index" method. Meanwhile, in an event of the detection based on multiple existing detection methods, the "double-index" method is also employed for judgment, that is, the detection result is identified as positive only if both detection methods yield positive results simultaneously; and otherwise, the result is regarded as negative. For example, in an event of the combination of beta-Amyloid Accumulation + FDG-PET / fMRI (CSF / PET), only when the results from detections of both beta-Amyloid Accumulation and FDG-PET / fMRI (CSF / PET) are positive can the detection result be regarded as positive. The results are shown in Table 5.

[0064] Table 5 Comparison table of detection result of each antigen combination based on "double-index" method Combination Sensitivity Specificity The number of samples detected as positive Ratio The number of samples detected as negative Ratio Combination 1 60 20% 300 100% Combination 2 60 20% 297 99% Combination 3 57 19% 300 100% Combination 4 57 19% 300 100% Combination 5 66 22% 297 99% Combination 6 93 31% 294 98% Combination 7 102 34% 297 99% Combination 8 135 45% 294 98% Combination 9 177 59% 282 94% P-Amyloid Accumulation 117 39% \ \ FDG-PET / fMRI (CSF / PET) 72 24% \ \ Tau-mediated neuronal injury(CSF) 54 18% \ \ P-Amyloid Accumulation+FDG-PET / fMRI (CSF / PET) 72 24% \ \ P-Amyloid Accumulation+Tau-mediated neuronal injury(CSF) 42 14% \ \ FDG-PET / fMRI+Tau-mediated neuronal injury(CSF) 33 11%

[0065] Results indicate that the detection result of the "double-index" method was closer to the detection results of beta-Amyloid Accumulation and the like, and the specificity was obviously higher, suggesting that the detection accuracy of the "double-index" method was higher.

[0066] 3. Samples identified as positive by detection of beta-Amyloid and the like were detected by using each individual protein antigen or by using antigen compositions based on the "single-index" method or "double-index" method.

[0067] To further confirm the overlap between the positive results detected by the individual antigens or each antigen combination and the positive results detected by the existing methods, the samples identified as positive through the following methods in Table 5: beta-Amyloid Accumulation, FDG-PET / fMRI (CSF / PET), Tau-mediated neuronal injury (CSF), betaAmyloid Accumulation + FDG-PET / fMRI (CSF / PET),beta-Amyloid Accumulation + Tau-mediated neuronal injury (CSF), and FDG-PET / fMRI + Tau-mediated neuronal injury (CSF), were detected again by using each antigen combination. The results are shown in Table 6. The total number of the samples identified as positive in Table 6 corresponds to the number of the samples identified as positive through detection by each existing method in Table 5.

[0068] Table 6 Comparison table of detection result of each antigen or antigen combination Antigen or antigen Combination P-Amyloid Accumulation (CSF / PET) FDG-PET / fMRI Tau-mediated neuronal injury (CSF) P-Amyloid Accumulation +FDG-PET / fM (CSF / PET) P-Amyloid Accumulation +Tau-mediated neuronal injury (CSF) FDG-PET / fMRI +Tau-mediated neuronal injury (CSF) Total number 117 Total number 72 Total number 54 Total number 72 Total number 42 Total number 33 LGALS1 48 36 36 36 30 21 HIST1H2BD 48 36 33 36 30 24 RIOK2 57 45 18 45 18 18 KDM4D 60 45 18 45 18 18 SERF2 63 33 24 33 21 18 ADARB1 66 42 33 42 27 18 ICAM1 60 36 27 36 27 18 DOC2A 42 30 18 30 12 12 DNAJC8 36 21 15 21 9 9 Single-index combination 1 111 69 48 69 42 33 Single index Combination 2 114 69 54 69 42 33 Single-index combination 3 111 69 45 69 42 33 Single-index combination 4 108 63 54 63 42 33 Single-index combination 5 102 66 48 66 39 30 Single-index combination 6 117 72 51 72 42 33 Single-index combination 7 117 72 54 72 42 33 Single-index combination 8 117 72 54 72 42 33 Antigen or antigen Combination P-Amyloid Accumulation (CSF / PET) FDG-PET / fMRI Tau-mediated neuronal injury (CSF) P-Amyloid Accumulation +FDG-PET / fM (CSF / PET) P-Amyloid Accumulation +Tau-mediated neuronal injury (CSF) FDG-PET / fMRI +Tau-mediated neuronal injury (CSF) Total number 117 Total number 72 Total number 54 Total number 72 Total number 42 Total number 33 Single-index combination 9 117 72 54 72 42 33 Double-index combination 1 51 36 24 36 21 18 Double-index combination 2 51 30 18 30 15 12 Double-index combination 3 51 39 24 39 21 21 Double-index combination 4 54 30 18 30 15 12 Double-index combination 5 63 48 36 48 33 24 Double-index combination 6 81 54 45 54 39 30 Double-index combination 7 117 72 54 72 42 33 Double-index combination 8 117 72 54 72 42 33 Double-index combination 9 117 72 54 72 42 33

[0069] Results indicate that the detection results of the combinations 7, 8 and 9 had a high matching degree with those from the existing detection methods which were recognized to have higher accuracy, and patients who were regarded as positive through detection by the existing methods could be detected completely and accurately.

[0070] Example 4: Display of effect of protein compositions in combined detection of patients with early AD and middle AD 100 clinical samples were taken as positive samples with early AD, 100 clinical samples were taken as positive samples with middle AD, and a detection signal (S) of each sample was determined using the candidate antigens and combinations thereof as shown in Table 3 based on the method in Example 2. The samples (S>M+3 SD) with the detection signal (S)>cut off value were regarded as positive; and the samples (S<M+3 SD) with the detection signal (S)<cut off value were regarded as negative.

[0071] The specificity and sensitivity were calculated based on the positive and negative results of the samples. Wherein, specificity refers to the proportion of healthy subjects whose samples are correctly determined as negative, that is, the number of the negative samples which are correctly determined as negative divided by the total number of the negative samples. Sensitivity refers to the proportion of positive samples of enrolled patients that are determined as positive, that is, the number of the positive samples which are correctly determined as positive divided by the total number of the positive samples. The sensitivity and specificity of each protein to be tested as an antigen for sample detection are obtained through calculation. The results are shown in Table 7.

[0072] Table 7 Comparison table of detection result of each antigen or antigen combination Antigen or antigen Combination Early sensitivity Medium sensitivity Medium and early sensitivity Specificity LGALS1 46% 28% 37% 98% HIST1H2BD 36% 24% 30% 95% RIOK2 28% 20% 24% 96% KDM4D 44% 24% 34% 95% SERF2 34% 28% 31% 96% ADARB 1 42% 38% 40% 94% ICAM1 20% 16% 18% 94% DOC2A 18% 10% 14% 94% DNAJC8 36% 34% 35% 98% Single-index combination 1 68% 62% 65% 89% Single-index combination 2 68% 62% 65% 85% Single-index combination 3 70% 54% 62% 87% Single-index combination 4 74% 72% 73% 89% Single-index combination 5 72% 64% 68% 88% Single-index combination 6 74% 76% 75% 85% Single-index combination 7 80% 66% 73% 82% Single-index combination 8 80% 78% 79% 79% Single-index combination 9 94% 86% 90% 66% Double-index combination 1 36% 18% 27% 100% Double-index combination 2 24% 14% 19% 99% Double-index combination 3 24% 18% 21% 100% Double-index combination 4 32% 26% 29% 100% Antigen or antigen Combination Early sensitivity Medium sensitivity Medium and early sensitivity Specificity Double-index combination 5 46% 22% 34% 99% Double-index combination 6 52% 34% 43% 98% Double-index combination 7 50% 30% 40% 99% Double-index combination 8 58% 42% 50% 98% Double-index combination 9 78% 66% 72% 94%

[0073] Results indicate that the detection results of the combinations 5, 6, 7, 8, and 9 had higher specificity and better sensitivity at early and middle stages of AD.

[0074] The above-described examples are merely the description of preferred implementations of the present disclosure, and do not limit the scope of the present disclosure. Various modifications, variations, alterations, and substitutions made by those of ordinary skill in the art to the technical solutions of the present disclosure are intended to fall within the scope of protection identified by the claims of the present disclosure without departing from the design spirit of the present disclosure.

Claims

1. An antigen combination, wherein the antigen combination at least simultaneously comprises any two of the following proteins: DOC2A, LGALS1, KDM4D, and ADARB1.

2. The antigen combination according to claim 1, wherein an amino acid sequence of the DOC2A protein is shown in SEQ ID NO: 1, and / or an amino acid sequence of the LGALS1 protein is shown in SEQ ID NO: 2, and / or an amino acid sequence of the KDM4D protein is shown in SEQ ID NO:7, and / or an amino acid sequence of the ADARB1 protein is shown in SEQ ID NO: 9.

3. The antigen combination according to claim 1 or 2, wherein the antigen combination further comprises an SERF2 protein, and an amino acid sequence of the SERF2 protein is shown in SEQ ID NO: 6.

4. The antigen combination according to claim 3, wherein the antigen combination further comprises any one or more of the following proteins: HIST1H2BD, ICAM1, RIOK2, and DNAJC8.

5. The antigen combination according to claim 4, wherein an amino acid sequence of the HIST1H2BD protein is shown in SEQ ID NO: 3, and / or an amino acid sequence of the ICAM1 protein is shown in SEQ ID NO: 4, and / or an amino acid sequence of the RIOK2 protein is shown in SEQ ID NO: 5, and / or an amino acid sequence of the DNAJC8 protein is shown in SEQ ID NO: 8.

6. Application of the antigen combination as claimed in any one of claims 1 to 5 in preparation of products for detecting / identifying Alzheimer's disease (AD).

7. The application according to claim 6, wherein the antigen combination is applied in preparation of products for detecting / identifying AD at a middle stage or earlier.

8. A reagent or a kit for detecting / identifying AD prepared by using the antigen combination as claimed in any one of claims 1 to 5.

9. Application of an LGALS1 protein and / or an HIST1H2BD protein and / or an RIOK2 protein in preparation of products for detecting / identifying AD, wherein an amino acid sequence of the LGALS1 protein is shown in SEQ ID NO: 2, and / or an amino acid sequence of the HIST1H2BD protein is shown in SEQ ID NO: 3, and / or an amino acid sequence of the RIOK2 protein is shown in SEQ ID NO: 5.

10. Products for detecting / identifying AD prepared from the protein(s) according to claim